1656561931 has 2 divisors, whose sum is σ = 1656561932. Its totient is φ = 1656561930.

The previous prime is 1656561883. The next prime is 1656561943. The reversal of 1656561931 is 1391656561.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1656561931 - 2¹⁵ = 1656529163 is a prime.

It is a super-2 number, since 2×1656561931² = 5488394862476897522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1656561631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 828280965 + 828280966.

It is an arithmetic number, because the mean of its divisors is an integer number (828280966).

Almost surely, 2^1656561931 is an apocalyptic number.

1656561931 is a deficient number, since it is larger than the sum of its proper divisors (1).

1656561931 is an equidigital number, since it uses as much as digits as its factorization.

1656561931 is an evil number, because the sum of its binary digits is even.

The product of its digits is 145800, while the sum is 43.

The square root of 1656561931 is about 40700.8836636258. The cubic root of 1656561931 is about 1183.2301449574.

The spelling of 1656561931 in words is "one billion, six hundred fifty-six million, five hundred sixty-one thousand, nine hundred thirty-one".