641399939 has 2 divisors, whose sum is σ = 641399940. Its totient is φ = 641399938.

The previous prime is 641399923. The next prime is 641399963. The reversal of 641399939 is 939993146.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 641399939 - 2⁴ = 641399923 is a prime.

It is a super-2 number, since 2×641399939² = 822787763498407442, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (641399999) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320699969 + 320699970.

It is an arithmetic number, because the mean of its divisors is an integer number (320699970).

Almost surely, 2^641399939 is an apocalyptic number.

641399939 is a deficient number, since it is larger than the sum of its proper divisors (1).

641399939 is an equidigital number, since it uses as much as digits as its factorization.

641399939 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1417176, while the sum is 53.

The square root of 641399939 is about 25325.8748911069. The cubic root of 641399939 is about 862.4017678225.

The spelling of 641399939 in words is "six hundred forty-one million, three hundred ninety-nine thousand, nine hundred thirty-nine".