21723230920 has 16 divisors (see below), whose sum is σ = 48877269660. Its totient is φ = 8689292352.

The previous prime is 21723230869. The next prime is 21723230933. The reversal of 21723230920 is 2903232712.

It can be written as a sum of positive squares in 2 ways, for example, as 21690809284 + 32421636 = 147278^2 + 5694^2 .

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, 271540347 + ... + 271540426.

Almost surely, 2^21723230920 is an apocalyptic number.

21723230920 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21723230920 is an abundant number, since it is smaller than the sum of its proper divisors (27154038740).

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

21723230920 is a wasteful number, since it uses less digits than its factorization.

21723230920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 543080784 (or 543080780 counting only the distinct ones).

The product of its (nonzero) digits is 9072, while the sum is 31.

The spelling of 21723230920 in words is "twenty-one billion, seven hundred twenty-three million, two hundred thirty thousand, nine hundred twenty".