21653475684 has 12 divisors (see below), whose sum is σ = 50524776624. Its totient is φ = 7217825224.

The previous prime is 21653475661. The next prime is 21653475689. The reversal of 21653475684 is 48657435612.

It is a tau number, because it is divible by the number of its divisors (12).

It is not an unprimeable number, because it can be changed into a prime (21653475689) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 902228142 + ... + 902228165.

It is an arithmetic number, because the mean of its divisors is an integer number (4210398052).

Almost surely, 2^21653475684 is an apocalyptic number.

It is an amenable number.

21653475684 is an abundant number, since it is smaller than the sum of its proper divisors (28871300940).

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

21653475684 is a wasteful number, since it uses less digits than its factorization.

21653475684 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1804456314 (or 1804456312 counting only the distinct ones).

The product of its digits is 4838400, while the sum is 51.

The spelling of 21653475684 in words is "twenty-one billion, six hundred fifty-three million, four hundred seventy-five thousand, six hundred eighty-four".