21625625 has 20 divisors (see below), whose sum is σ = 30890112. Its totient is φ = 14826000.

The previous prime is 21625621. The next prime is 21625633. The reversal of 21625625 is 52652612.

It is not a de Polignac number, because 21625625 - 2² = 21625621 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21625621) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 1904 + ... + 6846.

Almost surely, 2^21625625 is an apocalyptic number.

21625625 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21625625 is a deficient number, since it is larger than the sum of its proper divisors (9264487).

21625625 is an frugal number, since it uses more digits than its factorization.

21625625 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4970 (or 4955 counting only the distinct ones).

The product of its digits is 7200, while the sum is 29.

The square root of 21625625 is about 4650.3360093653. The cubic root of 21625625 is about 278.6054167853.

The spelling of 21625625 in words is "twenty-one million, six hundred twenty-five thousand, six hundred twenty-five".