# Primes That Do Not Generate Primes When Any Single Digit Is Prepended

Giving a quick inspection at the list of prime numbers, you’d notice that 2 is the first prime number. However, prepending any single decimal digit to it would not produce other primes, that is, 12, 22, 32, 42, 52, 62, 72, 82 and 92 are composite numbers. Likewise, the third prime number, 5, also shares […]

# Curious Number Substrings

If you add all the substrings of 891, the sum is 198, which is the reverse of 891: 891 → 8 + 9 + 1 + 89 + 91 = 198 This is the only 3-digit number that has this property. There is also one 4-digit number with the same property. Can you find this […]

# What’s Next?: An Unorthodox Number Sequence

0, 0, 0, 0, 4, 9, 5, 1, 1, 0, 55, 55, 1, 0, 1, 9, ? What is the next number in the sequence?

# Curious Number Patterns #5: 9th Power Pattern, Münchhausen Numbers & 1729

To the Ninth Power 59 + 39 + 49 + 49 + 99 + 49 + 89 + 39 + 69 = 534494836 Münchhausen Numbers Münchhausen number is a number equal to the sum of its nonzero digits raised to each digit’s power. There are only two of these numbers besides the trivial 0 and 1. See A046253.