21502625 has 8 divisors (see below), whose sum is σ = 26835432. Its totient is φ = 17202000.

The previous prime is 21502583. The next prime is 21502627. The reversal of 21502625 is 52620512.

It can be written as a sum of positive squares in 4 ways, for example, as 305809 + 21196816 = 553^2 + 4604^2 .

It is a de Polignac number, because none of the positive numbers 2^k-21502625 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21502625.

It is not an unprimeable number, because it can be changed into a prime (21502627) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 85886 + ... + 86135.

It is an arithmetic number, because the mean of its divisors is an integer number (3354429).

Almost surely, 2^21502625 is an apocalyptic number.

21502625 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21502625 is a deficient number, since it is larger than the sum of its proper divisors (5332807).

21502625 is an equidigital number, since it uses as much as digits as its factorization.

21502625 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 172036 (or 172026 counting only the distinct ones).

The product of its (nonzero) digits is 1200, while the sum is 23.

The square root of 21502625 is about 4637.0923001381. The cubic root of 21502625 is about 278.0762044598.

The spelling of 21502625 in words is "twenty-one million, five hundred two thousand, six hundred twenty-five".