646993937 has 2 divisors, whose sum is σ = 646993938. Its totient is φ = 646993936.

The previous prime is 646993891. The next prime is 646993943. The reversal of 646993937 is 739399646.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 466387216 + 180606721 = 21596^2 + 13439^2 .

It is a cyclic number.

It is not a de Polignac number, because 646993937 - 2⁶ = 646993873 is a prime.

It is not a weakly prime, because it can be changed into another prime (646993967) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323496968 + 323496969.

It is an arithmetic number, because the mean of its divisors is an integer number (323496969).

Almost surely, 2^646993937 is an apocalyptic number.

It is an amenable number.

646993937 is a deficient number, since it is larger than the sum of its proper divisors (1).

646993937 is an equidigital number, since it uses as much as digits as its factorization.

646993937 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6613488, while the sum is 56.

The square root of 646993937 is about 25436.0755031117. The cubic root of 646993937 is about 864.9016725859.

The spelling of 646993937 in words is "six hundred forty-six million, nine hundred ninety-three thousand, nine hundred thirty-seven".