21357825 has 24 divisors (see below), whose sum is σ = 35497728. Its totient is φ = 11330880.

The previous prime is 21357803. The next prime is 21357827. The reversal of 21357825 is 52875312.

It is not a de Polignac number, because 21357825 - 2⁷ = 21357697 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21357827) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 16087 + ... + 17363.

It is an arithmetic number, because the mean of its divisors is an integer number (1479072).

Almost surely, 2^21357825 is an apocalyptic number.

21357825 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21357825 is a deficient number, since it is larger than the sum of its proper divisors (14139903).

21357825 is a wasteful number, since it uses less digits than its factorization.

21357825 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1513 (or 1508 counting only the distinct ones).

The product of its digits is 16800, while the sum is 33.

The square root of 21357825 is about 4621.4526936884. The cubic root of 21357825 is about 277.4506039828.

The spelling of 21357825 in words is "twenty-one million, three hundred fifty-seven thousand, eight hundred twenty-five".