646138579 has 2 divisors, whose sum is σ = 646138580. Its totient is φ = 646138578.

The previous prime is 646138573. The next prime is 646138667. The reversal of 646138579 is 975831646.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 646138579 - 2⁵ = 646138547 is a prime.

It is not a weakly prime, because it can be changed into another prime (646138573) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323069289 + 323069290.

It is an arithmetic number, because the mean of its divisors is an integer number (323069290).

Almost surely, 2^646138579 is an apocalyptic number.

646138579 is a deficient number, since it is larger than the sum of its proper divisors (1).

646138579 is an equidigital number, since it uses as much as digits as its factorization.

646138579 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1088640, while the sum is 49.

The square root of 646138579 is about 25419.2560670056. The cubic root of 646138579 is about 864.5203568940.

The spelling of 646138579 in words is "six hundred forty-six million, one hundred thirty-eight thousand, five hundred seventy-nine".