21158625 has 32 divisors (see below), whose sum is σ = 37290240. Its totient is φ = 10617600.

The previous prime is 21158563. The next prime is 21158633. The reversal of 21158625 is 52685112.

It is not a de Polignac number, because 21158625 - 2¹⁰ = 21157601 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21158592 and 21158601.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4716 + ... + 8034.

It is an arithmetic number, because the mean of its divisors is an integer number (1165320).

Almost surely, 2^21158625 is an apocalyptic number.

21158625 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21158625 is a deficient number, since it is larger than the sum of its proper divisors (16131615).

21158625 is a wasteful number, since it uses less digits than its factorization.

21158625 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3354 (or 3344 counting only the distinct ones).

The product of its digits is 4800, while the sum is 30.

The square root of 21158625 is about 4599.8505410502. The cubic root of 21158625 is about 276.5853335867.

The spelling of 21158625 in words is "twenty-one million, one hundred fifty-eight thousand, six hundred twenty-five".