21310625 has 20 divisors (see below), whose sum is σ = 30440256. Its totient is φ = 14610000.

The previous prime is 21310613. The next prime is 21310637. The reversal of 21310625 is 52601312.

It is an interprime number because it is at equal distance from previous prime (21310613) and next prime (21310637).

It is not a de Polignac number, because 21310625 - 2⁶ = 21310561 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21310597 and 21310606.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 1940 + ... + 6810.

Almost surely, 2^21310625 is an apocalyptic number.

21310625 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21310625 is a deficient number, since it is larger than the sum of its proper divisors (9129631).

21310625 is an frugal number, since it uses more digits than its factorization.

21310625 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4898 (or 4883 counting only the distinct ones).

The product of its (nonzero) digits is 360, while the sum is 20.

The square root of 21310625 is about 4616.3432498028. The cubic root of 21310625 is about 277.2460680598.

Adding to 21310625 its reverse (52601312), we get a palindrome (73911937).

The spelling of 21310625 in words is "twenty-one million, three hundred ten thousand, six hundred twenty-five".