15661312 has 36 divisors (see below), whose sum is σ = 31567536. Its totient is φ = 7754240.

The previous prime is 15661309. The next prime is 15661333. The reversal of 15661312 is 21316651.

15661312 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×15661312² = 490553387122688, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 33303 + ... + 33769.

It is an arithmetic number, because the mean of its divisors is an integer number (876876).

Almost surely, 2^15661312 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 15661312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (15783768).

15661312 is an abundant number, since it is smaller than the sum of its proper divisors (15906224).

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

15661312 is an equidigital number, since it uses as much as digits as its factorization.

15661312 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 614 (or 600 counting only the distinct ones).

The product of its digits is 1080, while the sum is 25.

The square root of 15661312 is about 3957.4375547821. The cubic root of 15661312 is about 250.1935141704.

Adding to 15661312 its reverse (21316651), we get a palindrome (36977963).

The spelling of 15661312 in words is "fifteen million, six hundred sixty-one thousand, three hundred twelve".