21387852672 has 32 divisors (see below), whose sum is σ = 56811484680. Its totient is φ = 7129284096.

The previous prime is 21387852667. The next prime is 21387852749. The reversal of 21387852672 is 27625878312.

It is a tau number, because it is divible by the number of its divisors (32).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 27848383 + ... + 27849150.

Almost surely, 2^21387852672 is an apocalyptic number.

It is an amenable number.

21387852672 is an abundant number, since it is smaller than the sum of its proper divisors (35423632008).

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

21387852672 is an equidigital number, since it uses as much as digits as its factorization.

21387852672 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55697550 (or 55697538 counting only the distinct ones).

The product of its digits is 2257920, while the sum is 51.

The spelling of 21387852672 in words is "twenty-one billion, three hundred eighty-seven million, eight hundred fifty-two thousand, six hundred seventy-two".