15648721 has 16 divisors (see below), whose sum is σ = 18360000. Its totient is φ = 13178880.

The previous prime is 15648713. The next prime is 15648739. The reversal of 15648721 is 12784651.

It is not a de Polignac number, because 15648721 - 2³ = 15648713 is a prime.

15648721 is a Rhonda number in base 10.

Its product of digits (13440) is a multiple of the sum of its prime divisors (1344).

It is not an unprimeable number, because it can be changed into a prime (15648701) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11905 + ... + 13153.

It is an arithmetic number, because the mean of its divisors is an integer number (1147500).

Almost surely, 2^15648721 is an apocalyptic number.

15648721 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

15648721 is a deficient number, since it is larger than the sum of its proper divisors (2711279).

15648721 is a wasteful number, since it uses less digits than its factorization.

15648721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1344.

The product of its digits is 13440, while the sum is 34.

The square root of 15648721 is about 3955.8464328131. The cubic root of 15648721 is about 250.1264480328.

The spelling of 15648721 in words is "fifteen million, six hundred forty-eight thousand, seven hundred twenty-one".