21722560 has 28 divisors (see below), whose sum is σ = 51727608. Its totient is φ = 8688896.

The previous prime is 21722543. The next prime is 21722587. The reversal of 21722560 is 6522712.

It is a super-2 number, since 2×21722560² = 943739225907200, which contains 22 as substring.

It is a congruent number.

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, 33622 + ... + 34261.

Almost surely, 2^21722560 is an apocalyptic number.

21722560 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21722560 is an abundant number, since it is smaller than the sum of its proper divisors (30005048).

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

21722560 is an equidigital number, since it uses as much as digits as its factorization.

21722560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 67900 (or 67890 counting only the distinct ones).

The product of its (nonzero) digits is 1680, while the sum is 25.

The square root of 21722560 is about 4660.7467212883. The cubic root of 21722560 is about 279.0210712793.

The spelling of 21722560 in words is "twenty-one million, seven hundred twenty-two thousand, five hundred sixty".