21621745424 has 40 divisors (see below), whose sum is σ = 44164256640. Its totient is φ = 10234211328.

The previous prime is 21621745361. The next prime is 21621745501. The reversal of 21621745424 is 42454712612.

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, 267164 + ... + 338555.

It is an arithmetic number, because the mean of its divisors is an integer number (1104106416).

Almost surely, 2^21621745424 is an apocalyptic number.

It is an amenable number.

21621745424 is an abundant number, since it is smaller than the sum of its proper divisors (22542511216).

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

21621745424 is a wasteful number, since it uses less digits than its factorization.

21621745424 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 605847 (or 605841 counting only the distinct ones).

The product of its digits is 107520, while the sum is 38.

The spelling of 21621745424 in words is "twenty-one billion, six hundred twenty-one million, seven hundred forty-five thousand, four hundred twenty-four".