64637891 has 2 divisors, whose sum is σ = 64637892. Its totient is φ = 64637890.

The previous prime is 64637869. The next prime is 64637917. The reversal of 64637891 is 19873646.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 64637891 - 2¹⁰ = 64636867 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (64637801) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32318945 + 32318946.

It is an arithmetic number, because the mean of its divisors is an integer number (32318946).

Almost surely, 2^64637891 is an apocalyptic number.

64637891 is a deficient number, since it is larger than the sum of its proper divisors (1).

64637891 is an equidigital number, since it uses as much as digits as its factorization.

64637891 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 217728, while the sum is 44.

The square root of 64637891 is about 8039.7693374872. The cubic root of 64637891 is about 401.3245486691.

The spelling of 64637891 in words is "sixty-four million, six hundred thirty-seven thousand, eight hundred ninety-one".