21601825 has 12 divisors (see below), whose sum is σ = 30613120. Its totient is φ = 14812560.

The previous prime is 21601819. The next prime is 21601831. The reversal of 21601825 is 52810612.

It is an interprime number because it is at equal distance from previous prime (21601819) and next prime (21601831).

It is not a de Polignac number, because 21601825 - 2³ = 21601817 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is a self number, because there is not a number n which added to its sum of digits gives 21601825.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 61545 + ... + 61894.

Almost surely, 2^21601825 is an apocalyptic number.

21601825 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21601825 is a deficient number, since it is larger than the sum of its proper divisors (9011295).

21601825 is a wasteful number, since it uses less digits than its factorization.

21601825 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 123456 (or 123451 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 25.

The square root of 21601825 is about 4647.7763500410. The cubic root of 21601825 is about 278.5031732215.

The spelling of 21601825 in words is "twenty-one million, six hundred one thousand, eight hundred twenty-five".