6400634939 has 2 divisors, whose sum is σ = 6400634940. Its totient is φ = 6400634938.

The previous prime is 6400634843. The next prime is 6400634951. The reversal of 6400634939 is 9394360046.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 6400634939 - 2¹² = 6400630843 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 6400634939.

It is not a weakly prime, because it can be changed into another prime (6400634239) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3200317469 + 3200317470.

It is an arithmetic number, because the mean of its divisors is an integer number (3200317470).

Almost surely, 2^6400634939 is an apocalyptic number.

6400634939 is a deficient number, since it is larger than the sum of its proper divisors (1).

6400634939 is an equidigital number, since it uses as much as digits as its factorization.

6400634939 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 419904, while the sum is 44.

The square root of 6400634939 is about 80003.9682703302. The cubic root of 6400634939 is about 1856.6969298684.

The spelling of 6400634939 in words is "six billion, four hundred million, six hundred thirty-four thousand, nine hundred thirty-nine".