21058720 has 24 divisors (see below), whose sum is σ = 49751604. Its totient is φ = 8423424.

The previous prime is 21058711. The next prime is 21058721. The reversal of 21058720 is 2785012.

It can be written as a sum of positive squares in 2 ways, for example, as 20034576 + 1024144 = 4476^2 + 1012^2 .

It is not an unprimeable number, because it can be changed into a prime (21058721) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 65649 + ... + 65968.

Almost surely, 2^21058720 is an apocalyptic number.

21058720 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21058720 is an abundant number, since it is smaller than the sum of its proper divisors (28692884).

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

21058720 is a wasteful number, since it uses less digits than its factorization.

21058720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 131632 (or 131624 counting only the distinct ones).

The product of its (nonzero) digits is 1120, while the sum is 25.

The square root of 21058720 is about 4588.9780997516. The cubic root of 21058720 is about 276.1493275805.

The spelling of 21058720 in words is "twenty-one million, fifty-eight thousand, seven hundred twenty".