64632991 has 2 divisors, whose sum is σ = 64632992. Its totient is φ = 64632990.

The previous prime is 64632989. The next prime is 64633021. The reversal of 64632991 is 19923646.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 64632991 - 2¹ = 64632989 is a prime.

Together with 64632989, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (64632941) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32316495 + 32316496.

It is an arithmetic number, because the mean of its divisors is an integer number (32316496).

Almost surely, 2^64632991 is an apocalyptic number.

64632991 is a deficient number, since it is larger than the sum of its proper divisors (1).

64632991 is an equidigital number, since it uses as much as digits as its factorization.

64632991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 69984, while the sum is 40.

The square root of 64632991 is about 8039.4645966009. The cubic root of 64632991 is about 401.3144073523.

The spelling of 64632991 in words is "sixty-four million, six hundred thirty-two thousand, nine hundred ninety-one".