21153971504 has 20 divisors (see below), whose sum is σ = 41246880864. Its totient is φ = 10509615168.

The previous prime is 21153971491. The next prime is 21153971533. The reversal of 21153971504 is 40517935112.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4208072 + ... + 4213095.

Almost surely, 2^21153971504 is an apocalyptic number.

It is an amenable number.

21153971504 is a deficient number, since it is larger than the sum of its proper divisors (20092909360).

21153971504 is a wasteful number, since it uses less digits than its factorization.

21153971504 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8421332 (or 8421326 counting only the distinct ones).

The product of its (nonzero) digits is 37800, while the sum is 38.

The spelling of 21153971504 in words is "twenty-one billion, one hundred fifty-three million, nine hundred seventy-one thousand, five hundred four".