21862720 has 56 divisors (see below), whose sum is σ = 56802528. Its totient is φ = 7948800.

The previous prime is 21862699. The next prime is 21862739. The reversal of 21862720 is 2726812.

It is a congruent number.

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, 415 + ... + 6625.

Almost surely, 2^21862720 is an apocalyptic number.

21862720 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21862720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28401264).

21862720 is an abundant number, since it is smaller than the sum of its proper divisors (34939808).

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

21862720 is a wasteful number, since it uses less digits than its factorization.

21862720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6239 (or 6229 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 28.

The square root of 21862720 is about 4675.7587619551. The cubic root of 21862720 is about 279.6198923904.

The spelling of 21862720 in words is "twenty-one million, eight hundred sixty-two thousand, seven hundred twenty".