64191917 has 6 divisors (see below), whose sum is σ = 66330414. Its totient is φ = 62120280.

The previous prime is 64191913. The next prime is 64191931. The reversal of 64191917 is 71919146.

It can be written as a sum of positive squares in only one way, i.e., 46936201 + 17255716 = 6851^2 + 4154^2 .

It is not a de Polignac number, because 64191917 - 2² = 64191913 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64191913) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 32438 + ... + 34359.

It is an arithmetic number, because the mean of its divisors is an integer number (11055069).

Almost surely, 2^64191917 is an apocalyptic number.

It is an amenable number.

64191917 is a deficient number, since it is larger than the sum of its proper divisors (2138497).

64191917 is an equidigital number, since it uses as much as digits as its factorization.

64191917 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 66859 (or 66828 counting only the distinct ones).

The product of its digits is 13608, while the sum is 38.

The square root of 64191917 is about 8011.9858337369. The cubic root of 64191917 is about 400.3994280936.

The spelling of 64191917 in words is "sixty-four million, one hundred ninety-one thousand, nine hundred seventeen".