64970991 has 40 divisors (see below), whose sum is σ = 106373520. Its totient is φ = 39336192.

The previous prime is 64970987. The next prime is 64970993. The reversal of 64970991 is 19907946.

It is not a de Polignac number, because 64970991 - 2² = 64970987 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64970993) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 39120 + ... + 40746.

It is an arithmetic number, because the mean of its divisors is an integer number (2659338).

Almost surely, 2^64970991 is an apocalyptic number.

64970991 is a deficient number, since it is larger than the sum of its proper divisors (41402529).

64970991 is a wasteful number, since it uses less digits than its factorization.

64970991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1685 (or 1676 counting only the distinct ones).

The product of its (nonzero) digits is 122472, while the sum is 45.

The square root of 64970991 is about 8060.4584857190. The cubic root of 64970991 is about 402.0127529926.

The spelling of 64970991 in words is "sixty-four million, nine hundred seventy thousand, nine hundred ninety-one".