15728121 has 32 divisors (see below), whose sum is σ = 24624000. Its totient is φ = 9906624.

The previous prime is 15728117. The next prime is 15728123. The reversal of 15728121 is 12182751.

It is not a de Polignac number, because 15728121 - 2² = 15728117 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15728123) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 41310 + ... + 41688.

It is an arithmetic number, because the mean of its divisors is an integer number (769500).

Almost surely, 2^15728121 is an apocalyptic number.

It is an amenable number.

15728121 is a deficient number, since it is larger than the sum of its proper divisors (8895879).

15728121 is a wasteful number, since it uses less digits than its factorization.

15728121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 470 (or 464 counting only the distinct ones).

The product of its digits is 1120, while the sum is 27.

The square root of 15728121 is about 3965.8695137384. The cubic root of 15728121 is about 250.5487731773.

The spelling of 15728121 in words is "fifteen million, seven hundred twenty-eight thousand, one hundred twenty-one".