21685375710 has 24 divisors (see below), whose sum is σ = 56381977080. Its totient is φ = 5782766832.

The previous prime is 21685375633. The next prime is 21685375757. The reversal of 21685375710 is 1757358612.

It is a happy number.

21685375710 is a `hidden beast` number, since 2 + 1 + 68 + 537 + 57 + 1 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 120474220 + ... + 120474399.

It is an arithmetic number, because the mean of its divisors is an integer number (2349249045).

Almost surely, 2^21685375710 is an apocalyptic number.

21685375710 is an abundant number, since it is smaller than the sum of its proper divisors (34696601370).

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

21685375710 is a wasteful number, since it uses less digits than its factorization.

21685375710 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 240948632 (or 240948629 counting only the distinct ones).

The product of its (nonzero) digits is 352800, while the sum is 45.

The spelling of 21685375710 in words is "twenty-one billion, six hundred eighty-five million, three hundred seventy-five thousand, seven hundred ten".