15665625 has 36 divisors (see below), whose sum is σ = 28334124. Its totient is φ = 8340000.

The previous prime is 15665623. The next prime is 15665641. The reversal of 15665625 is 52656651.

It is a happy number.

It can be written as a sum of positive squares in 6 ways, for example, as 15116544 + 549081 = 3888^2 + 741^2 .

It is not a de Polignac number, because 15665625 - 2¹ = 15665623 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 15665625.

It is not an unprimeable number, because it can be changed into a prime (15665623) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 27847 + ... + 28403.

It is an arithmetic number, because the mean of its divisors is an integer number (787059).

Almost surely, 2^15665625 is an apocalyptic number.

15665625 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

15665625 is a deficient number, since it is larger than the sum of its proper divisors (12668499).

15665625 is an frugal number, since it uses more digits than its factorization.

15665625 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 588 (or 565 counting only the distinct ones).

The product of its digits is 54000, while the sum is 36.

The square root of 15665625 is about 3957.9824405876. The cubic root of 15665625 is about 250.2164791597.

It can be divided in two parts, 15665 and 625, that added together give a triangular number (16290 = T₁₈₀).

The spelling of 15665625 in words is "fifteen million, six hundred sixty-five thousand, six hundred twenty-five".