15661020736 has 21 divisors (see below), whose sum is σ = 31079324811. Its totient is φ = 7830009792.

The previous prime is 15661020707. The next prime is 15661020757. The reversal of 15661020736 is 63702016651.

The square root of 15661020736 is 125144.

It is a perfect power (a square), and thus also a powerful number.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 15661020695 and 15661020704.

It is an unprimeable number.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 993331 + ... + 1008973.

Almost surely, 2^15661020736 is an apocalyptic number.

15661020736 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

15661020736 is the 125144-th square number.

It is an amenable number.

15661020736 is a deficient number, since it is larger than the sum of its proper divisors (15418304075).

15661020736 is an frugal number, since it uses more digits than its factorization.

15661020736 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31298 (or 15645 counting only the distinct ones).

The product of its (nonzero) digits is 45360, while the sum is 37.

The spelling of 15661020736 in words is "fifteen billion, six hundred sixty-one million, twenty thousand, seven hundred thirty-six".