21560725 has 18 divisors (see below), whose sum is σ = 28228290. Its totient is φ = 16333920.

The previous prime is 21560719. The next prime is 21560767. The reversal of 21560725 is 52706512.

It can be written as a sum of positive squares in 3 ways, for example, as 244036 + 21316689 = 494^2 + 4617^2 .

It is not a de Polignac number, because 21560725 - 2⁷ = 21560597 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21560693 and 21560702.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 7831 + ... + 10219.

Almost surely, 2^21560725 is an apocalyptic number.

21560725 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21560725 is a deficient number, since it is larger than the sum of its proper divisors (6667565).

21560725 is a wasteful number, since it uses less digits than its factorization.

21560725 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2437 (or 2413 counting only the distinct ones).

The product of its (nonzero) digits is 4200, while the sum is 28.

The square root of 21560725 is about 4643.3527757430. The cubic root of 21560725 is about 278.3264327913.

The spelling of 21560725 in words is "twenty-one million, five hundred sixty thousand, seven hundred twenty-five".