646138667 has 2 divisors, whose sum is σ = 646138668. Its totient is φ = 646138666.

The previous prime is 646138579. The next prime is 646138693. The reversal of 646138667 is 766831646.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 646138667 - 2¹⁴ = 646122283 is a prime.

It is not a weakly prime, because it can be changed into another prime (646128667) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323069333 + 323069334.

It is an arithmetic number, because the mean of its divisors is an integer number (323069334).

Almost surely, 2^646138667 is an apocalyptic number.

646138667 is a deficient number, since it is larger than the sum of its proper divisors (1).

646138667 is an equidigital number, since it uses as much as digits as its factorization.

646138667 is an evil number, because the sum of its binary digits is even.

The product of its digits is 870912, while the sum is 47.

The square root of 646138667 is about 25419.2577979767. The cubic root of 646138667 is about 864.5203961414.

The spelling of 646138667 in words is "six hundred forty-six million, one hundred thirty-eight thousand, six hundred sixty-seven".