646633679 has 2 divisors, whose sum is σ = 646633680. Its totient is φ = 646633678.

The previous prime is 646633651. The next prime is 646633693. The reversal of 646633679 is 976336646.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-646633679 is a prime.

It is a super-2 number, since 2×646633679² = 836270229634150082, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (646633609) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323316839 + 323316840.

It is an arithmetic number, because the mean of its divisors is an integer number (323316840).

Almost surely, 2^646633679 is an apocalyptic number.

646633679 is a deficient number, since it is larger than the sum of its proper divisors (1).

646633679 is an equidigital number, since it uses as much as digits as its factorization.

646633679 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2939328, while the sum is 50.

The square root of 646633679 is about 25428.9928821414. The cubic root of 646633679 is about 864.7411117834.

The spelling of 646633679 in words is "six hundred forty-six million, six hundred thirty-three thousand, six hundred seventy-nine".