21000120999972 has 48 divisors (see below), whose sum is σ = 49098809760000. Its totient is φ = 6985966256640.

The previous prime is 21000120999941. The next prime is 21000120999973. The reversal of 21000120999972 is 27999902100012.

It is not an unprimeable number, because it can be changed into a prime (21000120999973) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 158735772 + ... + 158868012.

It is an arithmetic number, because the mean of its divisors is an integer number (1022891870000).

Almost surely, 2^{21000120999972} is an apocalyptic number.

It is an amenable number.

21000120999972 is an abundant number, since it is smaller than the sum of its proper divisors (28098688760028).

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

21000120999972 is a wasteful number, since it uses less digits than its factorization.

21000120999972 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 158756 (or 158754 counting only the distinct ones).

The product of its (nonzero) digits is 367416, while the sum is 51.

The spelling of 21000120999972 in words is "twenty-one trillion, one hundred twenty million, nine hundred ninety-nine thousand, nine hundred seventy-two".