646616137 has 2 divisors, whose sum is σ = 646616138. Its totient is φ = 646616136.

The previous prime is 646616123. The next prime is 646616141. The reversal of 646616137 is 731616646.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 507871296 + 138744841 = 22536^2 + 11779^2 .

It is a cyclic number.

It is not a de Polignac number, because 646616137 - 2¹⁵ = 646583369 is a prime.

It is a super-2 number, since 2×646616137² = 836224857257605538, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 646616137.

It is not a weakly prime, because it can be changed into another prime (646616147) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323308068 + 323308069.

It is an arithmetic number, because the mean of its divisors is an integer number (323308069).

Almost surely, 2^646616137 is an apocalyptic number.

It is an amenable number.

646616137 is a deficient number, since it is larger than the sum of its proper divisors (1).

646616137 is an equidigital number, since it uses as much as digits as its factorization.

646616137 is an evil number, because the sum of its binary digits is even.

The product of its digits is 108864, while the sum is 40.

The square root of 646616137 is about 25428.6479585526. The cubic root of 646616137 is about 864.7332920929.

The spelling of 646616137 in words is "six hundred forty-six million, six hundred sixteen thousand, one hundred thirty-seven".