21163604521 has 8 divisors (see below), whose sum is σ = 22678506144. Its totient is φ = 19678701120.

The previous prime is 21163604513. The next prime is 21163604563. The reversal of 21163604521 is 12540636112.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21163604521 - 2³ = 21163604513 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21113604521) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7498095 + ... + 7500916.

It is an arithmetic number, because the mean of its divisors is an integer number (2834813268).

Almost surely, 2^21163604521 is an apocalyptic number.

It is an amenable number.

21163604521 is a deficient number, since it is larger than the sum of its proper divisors (1514901623).

21163604521 is a wasteful number, since it uses less digits than its factorization.

21163604521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14999111.

The product of its (nonzero) digits is 8640, while the sum is 31.

The spelling of 21163604521 in words is "twenty-one billion, one hundred sixty-three million, six hundred four thousand, five hundred twenty-one".