15661066566 has 32 divisors (see below), whose sum is σ = 31933022688. Its totient is φ = 5118663680.

The previous prime is 15661066529. The next prime is 15661066609. The reversal of 15661066566 is 66566016651.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 525136 + ... + 554156.

It is an arithmetic number, because the mean of its divisors is an integer number (997906959).

Almost surely, 2^15661066566 is an apocalyptic number.

15661066566 is an abundant number, since it is smaller than the sum of its proper divisors (16271956122).

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

15661066566 is a wasteful number, since it uses less digits than its factorization.

15661066566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30776.

The product of its (nonzero) digits is 1166400, while the sum is 48.

The spelling of 15661066566 in words is "fifteen billion, six hundred sixty-one million, sixty-six thousand, five hundred sixty-six".