1661715657 has 12 divisors (see below), whose sum is σ = 2743149760. Its totient is φ = 949551768.

The previous prime is 1661715611. The next prime is 1661715697. The reversal of 1661715657 is 7565171661.

1661715657 is a `hidden beast` number, since 16 + 6 + 1 + 71 + 565 + 7 = 666.

It is not a de Polignac number, because 1661715657 - 2⁸ = 1661715401 is a prime.

It is a super-2 number, since 2×1661715657² = 5522597849437883298, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1661715697) 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, 13188157 + ... + 13188282.

Almost surely, 2^1661715657 is an apocalyptic number.

It is an amenable number.

1661715657 is a deficient number, since it is larger than the sum of its proper divisors (1081434103).

1661715657 is a wasteful number, since it uses less digits than its factorization.

1661715657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26376452 (or 26376449 counting only the distinct ones).

The product of its digits is 264600, while the sum is 45.

The square root of 1661715657 is about 40764.1467100686. The cubic root of 1661715657 is about 1184.4559228543.

The spelling of 1661715657 in words is "one billion, six hundred sixty-one million, seven hundred fifteen thousand, six hundred fifty-seven".