21604456960 has 40 divisors (see below), whose sum is σ = 51800067396. Its totient is φ = 8641781760.

The previous prime is 21604456931. The next prime is 21604456961. The reversal of 21604456960 is 6965440612.

It can be written as a sum of positive squares in 2 ways, for example, as 20145828096 + 1458628864 = 141936^2 + 38192^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is not an unprimeable number, because it can be changed into a prime (21604456961) 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, 4217061 + ... + 4222180.

Almost surely, 2^21604456960 is an apocalyptic number.

21604456960 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21604456960 is an abundant number, since it is smaller than the sum of its proper divisors (30195610436).

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

21604456960 is an frugal number, since it uses more digits than its factorization.

21604456960 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8439264 (or 8439248 counting only the distinct ones).

The product of its (nonzero) digits is 311040, while the sum is 43.

The spelling of 21604456960 in words is "twenty-one billion, six hundred four million, four hundred fifty-six thousand, nine hundred sixty".