21634625 has 16 divisors (see below), whose sum is σ = 28591056. Its totient is φ = 16288000.

The previous prime is 21634607. The next prime is 21634631. The reversal of 21634625 is 52643612.

It can be written as a sum of positive squares in 8 ways, for example, as 3418801 + 18215824 = 1849^2 + 4268^2 .

It is not a de Polignac number, because 21634625 - 2¹⁴ = 21618241 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2966 + ... + 7215.

It is an arithmetic number, because the mean of its divisors is an integer number (1786941).

Almost surely, 2^21634625 is an apocalyptic number.

21634625 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21634625 is a deficient number, since it is larger than the sum of its proper divisors (6956431).

21634625 is a wasteful number, since it uses less digits than its factorization.

21634625 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10213 (or 10203 counting only the distinct ones).

The product of its digits is 8640, while the sum is 29.

The square root of 21634625 is about 4651.3035807180. The cubic root of 21634625 is about 278.6440607704.

The spelling of 21634625 in words is "twenty-one million, six hundred thirty-four thousand, six hundred twenty-five".