64997691 has 12 divisors (see below), whose sum is σ = 95258856. Its totient is φ = 39392320.

The previous prime is 64997687. The next prime is 64997707. The reversal of 64997691 is 19679946.

It is not a de Polignac number, because 64997691 - 2² = 64997687 is a prime.

It is not an unprimeable number, because it can be changed into a prime (64997791) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 89166 + ... + 89891.

It is an arithmetic number, because the mean of its divisors is an integer number (7938238).

Almost surely, 2^64997691 is an apocalyptic number.

64997691 is a deficient number, since it is larger than the sum of its proper divisors (30261165).

64997691 is a wasteful number, since it uses less digits than its factorization.

64997691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 179082 (or 179071 counting only the distinct ones).

The product of its digits is 734832, while the sum is 51.

The square root of 64997691 is about 8062.1145489257. The cubic root of 64997691 is about 402.0678148508.

The spelling of 64997691 in words is "sixty-four million, nine hundred ninety-seven thousand, six hundred ninety-one".