121515555231 has 48 divisors (see below), whose sum is σ = 203573360640. Its totient is φ = 68409360000.

The previous prime is 121515555199. The next prime is 121515555247. The reversal of 121515555231 is 132555515121.

121515555231 is a `hidden beast` number, since 1 + 2 + 1 + 51 + 55 + 552 + 3 + 1 = 666.

It is not a de Polignac number, because 121515555231 - 2⁵ = 121515555199 is a prime.

It is a super-2 number, since 2×121515555231² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121515505231) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 4212106 + ... + 4240856.

It is an arithmetic number, because the mean of its divisors is an integer number (4241111680).

Almost surely, 2^121515555231 is an apocalyptic number.

121515555231 is a deficient number, since it is larger than the sum of its proper divisors (82057805409).

121515555231 is a wasteful number, since it uses less digits than its factorization.

121515555231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29756 (or 29753 counting only the distinct ones).

The product of its digits is 37500, while the sum is 36.

The spelling of 121515555231 in words is "one hundred twenty-one billion, five hundred fifteen million, five hundred fifty-five thousand, two hundred thirty-one".