15640725 has 24 divisors (see below), whose sum is σ = 26114400. Its totient is φ = 8259520.

The previous prime is 15640717. The next prime is 15640727. The reversal of 15640725 is 52704651.

It is not a de Polignac number, because 15640725 - 2³ = 15640717 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 15640692 and 15640701.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15640727) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 7051 + ... + 8999.

It is an arithmetic number, because the mean of its divisors is an integer number (1088100).

Almost surely, 2^15640725 is an apocalyptic number.

15640725 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

15640725 is a deficient number, since it is larger than the sum of its proper divisors (10473675).

15640725 is a wasteful number, since it uses less digits than its factorization.

15640725 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2069 (or 2064 counting only the distinct ones).

The product of its (nonzero) digits is 8400, while the sum is 30.

The square root of 15640725 is about 3954.8356476597. The cubic root of 15640725 is about 250.0838385479.

The spelling of 15640725 in words is "fifteen million, six hundred forty thousand, seven hundred twenty-five".