15561728 has 88 divisors (see below), whose sum is σ = 38516352. Its totient is φ = 6119424.

The previous prime is 15561697. The next prime is 15561737. The reversal of 15561728 is 82716551.

It is a nialpdrome in base 16.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 93101 + ... + 93267.

Almost surely, 2^15561728 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 15561728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (19258176).

15561728 is an abundant number, since it is smaller than the sum of its proper divisors (22954624).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

15561728 is a wasteful number, since it uses less digits than its factorization.

15561728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 207 (or 189 counting only the distinct ones).

The product of its digits is 16800, while the sum is 35.

The square root of 15561728 is about 3944.8356112771. The cubic root of 15561728 is about 249.6620928140.

The spelling of 15561728 in words is "fifteen million, five hundred sixty-one thousand, seven hundred twenty-eight".