231515520120440 has 32 divisors (see below), whose sum is σ = 548326231866000. Its totient is φ = 87732197097984.

The previous prime is 231515520120431. The next prime is 231515520120449. The reversal of 231515520120440 is 44021025515132.

It is an interprime number because it is at equal distance from previous prime (231515520120431) and next prime (231515520120449).

It is a self number, because there is not a number n which added to its sum of digits gives 231515520120440.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (231515520120449) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 152312841425 + ... + 152312842944.

Almost surely, 2^{231515520120440} is an apocalyptic number.

231515520120440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

231515520120440 is an abundant number, since it is smaller than the sum of its proper divisors (316810711745560).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

231515520120440 is a wasteful number, since it uses less digits than its factorization.

231515520120440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 304625684399 (or 304625684395 counting only the distinct ones).

The product of its (nonzero) digits is 48000, while the sum is 35.

Adding to 231515520120440 its reverse (44021025515132), we get a palindrome (275536545635572).

The spelling of 231515520120440 in words is "two hundred thirty-one trillion, five hundred fifteen billion, five hundred twenty million, one hundred twenty thousand, four hundred forty".