646401911 has 2 divisors, whose sum is σ = 646401912. Its totient is φ = 646401910.

The previous prime is 646401893. The next prime is 646401947. The reversal of 646401911 is 119104646.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 646401911 - 2²² = 642207607 is a prime.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (646401961) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323200955 + 323200956.

It is an arithmetic number, because the mean of its divisors is an integer number (323200956).

Almost surely, 2^646401911 is an apocalyptic number.

646401911 is a deficient number, since it is larger than the sum of its proper divisors (1).

646401911 is an equidigital number, since it uses as much as digits as its factorization.

646401911 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5184, while the sum is 32.

The square root of 646401911 is about 25424.4353132965. The cubic root of 646401911 is about 864.6377852405.

The spelling of 646401911 in words is "six hundred forty-six million, four hundred one thousand, nine hundred eleven".