21370720 has 48 divisors (see below), whose sum is σ = 57703968. Its totient is φ = 7326720.

The previous prime is 21370693. The next prime is 21370721. The reversal of 21370720 is 2707312.

It is a junction number, because it is equal to n+sod(n) for n = 21370691 and 21370700.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21370721) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8421 + ... + 10660.

It is an arithmetic number, because the mean of its divisors is an integer number (1202166).

Almost surely, 2^21370720 is an apocalyptic number.

21370720 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21370720 is an abundant number, since it is smaller than the sum of its proper divisors (36333248).

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

21370720 is a wasteful number, since it uses less digits than its factorization.

21370720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19103 (or 19095 counting only the distinct ones).

The product of its (nonzero) digits is 588, while the sum is 22.

The square root of 21370720 is about 4622.8476072655. The cubic root of 21370720 is about 277.5064306061.

The spelling of 21370720 in words is "twenty-one million, three hundred seventy thousand, seven hundred twenty".