21640032420 has 48 divisors (see below), whose sum is σ = 60668250048. Its totient is φ = 5763422080.

The previous prime is 21640032413. The next prime is 21640032431. The reversal of 21640032420 is 2423004612.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 178446 + ... + 274085.

It is an arithmetic number, because the mean of its divisors is an integer number (1263921876).

Almost surely, 2^21640032420 is an apocalyptic number.

21640032420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21640032420 is an abundant number, since it is smaller than the sum of its proper divisors (39028217628).

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

21640032420 is a wasteful number, since it uses less digits than its factorization.

21640032420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 453340 (or 453338 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 24.

The spelling of 21640032420 in words is "twenty-one billion, six hundred forty million, thirty-two thousand, four hundred twenty".