15661442973 has 12 divisors (see below), whose sum is σ = 22952859104. Its totient is φ = 9491783400.

The previous prime is 15661442959. The next prime is 15661442981. The reversal of 15661442973 is 37924416651.

It is not a de Polignac number, because 15661442973 - 2³² = 11366475677 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15661442903) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 21571873 + ... + 21572598.

Almost surely, 2^15661442973 is an apocalyptic number.

It is an amenable number.

15661442973 is a deficient number, since it is larger than the sum of its proper divisors (7291416131).

15661442973 is a wasteful number, since it uses less digits than its factorization.

15661442973 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43144496 (or 43144485 counting only the distinct ones).

The product of its digits is 1088640, while the sum is 48.

The spelling of 15661442973 in words is "fifteen billion, six hundred sixty-one million, four hundred forty-two thousand, nine hundred seventy-three".