21157560 has 48 divisors (see below), whose sum is σ = 68763240. Its totient is φ = 5641920.

The previous prime is 21157529. The next prime is 21157573. The reversal of 21157560 is 6575112.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 29026 + ... + 29745.

Almost surely, 2^21157560 is an apocalyptic number.

21157560 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21157560 is an abundant number, since it is smaller than the sum of its proper divisors (47605680).

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

21157560 is a wasteful number, since it uses less digits than its factorization.

21157560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 58788 (or 58781 counting only the distinct ones).

The product of its (nonzero) digits is 2100, while the sum is 27.

The square root of 21157560 is about 4599.7347749626. The cubic root of 21157560 is about 276.5806929524.

The spelling of 21157560 in words is "twenty-one million, one hundred fifty-seven thousand, five hundred sixty".