21604728452 has 12 divisors (see below), whose sum is σ = 37909640076. Its totient is φ = 10773402720.

The previous prime is 21604728403. The next prime is 21604728461. The reversal of 21604728452 is 25482740612.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 17335935556 + 4268792896 = 131666^2 + 65336^2 .

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, 7238699 + ... + 7241682.

It is an arithmetic number, because the mean of its divisors is an integer number (3159136673).

Almost surely, 2^21604728452 is an apocalyptic number.

It is an amenable number.

21604728452 is a deficient number, since it is larger than the sum of its proper divisors (16304911624).

21604728452 is a wasteful number, since it uses less digits than its factorization.

21604728452 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14480758 (or 14480756 counting only the distinct ones).

The product of its (nonzero) digits is 215040, while the sum is 41.

The spelling of 21604728452 in words is "twenty-one billion, six hundred four million, seven hundred twenty-eight thousand, four hundred fifty-two".