21115531123504 has 10 divisors (see below), whose sum is σ = 40911341551820. Its totient is φ = 10557765561744.

The previous prime is 21115531123481. The next prime is 21115531123571. The reversal of 21115531123504 is 40532113551112.

It is a self number, because there is not a number n which added to its sum of digits gives 21115531123504.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 659860347594 + ... + 659860347625.

It is an arithmetic number, because the mean of its divisors is an integer number (4091134155182).

Almost surely, 2^{21115531123504} is an apocalyptic number.

It is an amenable number.

21115531123504 is a deficient number, since it is larger than the sum of its proper divisors (19795810428316).

21115531123504 is a wasteful number, since it uses less digits than its factorization.

21115531123504 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1319720695227 (or 1319720695221 counting only the distinct ones).

The product of its (nonzero) digits is 18000, while the sum is 34.

Adding to 21115531123504 its reverse (40532113551112), we get a palindrome (61647644674616).

The spelling of 21115531123504 in words is "twenty-one trillion, one hundred fifteen billion, five hundred thirty-one million, one hundred twenty-three thousand, five hundred four".