634461991 has 2 divisors, whose sum is σ = 634461992. Its totient is φ = 634461990.

The previous prime is 634461979. The next prime is 634462007. The reversal of 634461991 is 199164436.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 634461991 - 2⁵ = 634461959 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (634461911) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 317230995 + 317230996.

It is an arithmetic number, because the mean of its divisors is an integer number (317230996).

Almost surely, 2^634461991 is an apocalyptic number.

634461991 is a deficient number, since it is larger than the sum of its proper divisors (1).

634461991 is an equidigital number, since it uses as much as digits as its factorization.

634461991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 139968, while the sum is 43.

The square root of 634461991 is about 25188.5289566501. The cubic root of 634461991 is about 859.2809886291.

The spelling of 634461991 in words is "six hundred thirty-four million, four hundred sixty-one thousand, nine hundred ninety-one".