21569730920 has 32 divisors (see below), whose sum is σ = 49032232200. Its totient is φ = 8538943488.

The previous prime is 21569730899. The next prime is 21569730953. The reversal of 21569730920 is 2903796512.

It can be written as a sum of positive squares in 4 ways, for example, as 14601822244 + 6967908676 = 120838^2 + 83474^2 .

It is a super-2 number, since 2×21569730920² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2775725 + ... + 2783484.

Almost surely, 2^21569730920 is an apocalyptic number.

21569730920 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21569730920 is an abundant number, since it is smaller than the sum of its proper divisors (27462501280).

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

21569730920 is a wasteful number, since it uses less digits than its factorization.

21569730920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5559317 (or 5559313 counting only the distinct ones).

The product of its (nonzero) digits is 204120, while the sum is 44.

The spelling of 21569730920 in words is "twenty-one billion, five hundred sixty-nine million, seven hundred thirty thousand, nine hundred twenty".