20921158972 has 18 divisors (see below), whose sum is σ = 42589502592. Its totient is φ = 8966210904.

The previous prime is 20921158943. The next prime is 20921159003. The reversal of 20921158972 is 27985112902.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 53370108 + ... + 53370499.

Almost surely, 2^20921158972 is an apocalyptic number.

It is an amenable number.

20921158972 is an abundant number, since it is smaller than the sum of its proper divisors (21668343620).

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

20921158972 is a wasteful number, since it uses less digits than its factorization.

20921158972 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 106740625 (or 106740616 counting only the distinct ones).

The product of its (nonzero) digits is 181440, while the sum is 46.

The spelling of 20921158972 in words is "twenty billion, nine hundred twenty-one million, one hundred fifty-eight thousand, nine hundred seventy-two".