21542625 has 64 divisors (see below), whose sum is σ = 42981120. Its totient is φ = 10584000.

The previous prime is 21542623. The next prime is 21542639. The reversal of 21542625 is 52624512.

21542625 is a `hidden beast` number, since 215 + 426 + 25 = 666.

It is not a de Polignac number, because 21542625 - 2¹ = 21542623 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (21542623) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 43630 + ... + 44120.

It is an arithmetic number, because the mean of its divisors is an integer number (671580).

Almost surely, 2^21542625 is an apocalyptic number.

21542625 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21542625 is a deficient number, since it is larger than the sum of its proper divisors (21438495).

21542625 is a wasteful number, since it uses less digits than its factorization.

21542625 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 528 (or 512 counting only the distinct ones).

The product of its digits is 4800, while the sum is 27.

The square root of 21542625 is about 4641.4033438175. The cubic root of 21542625 is about 278.2485269573.

The spelling of 21542625 in words is "twenty-one million, five hundred forty-two thousand, six hundred twenty-five".