15987666 has 16 divisors (see below), whose sum is σ = 32112000. Its totient is φ = 5306448.

The previous prime is 15987611. The next prime is 15987677. The reversal of 15987666 is 66678951.

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, 4141 + ... + 7008.

It is an arithmetic number, because the mean of its divisors is an integer number (2007000).

Almost surely, 2^15987666 is an apocalyptic number.

15987666 is an abundant number, since it is smaller than the sum of its proper divisors (16124334).

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

15987666 is a wasteful number, since it uses less digits than its factorization.

15987666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11393.

The product of its digits is 544320, while the sum is 48.

The square root of 15987666 is about 3998.4579527613. The cubic root of 15987666 is about 251.9194438913.

It can be divided in two parts, 15987 and 666, that added together give a triangular number (16653 = T₁₈₂).

The spelling of 15987666 in words is "fifteen million, nine hundred eighty-seven thousand, six hundred sixty-six".