64391687 has 4 divisors (see below), whose sum is σ = 66612120. Its totient is φ = 62171256.

The previous prime is 64391671. The next prime is 64391707. The reversal of 64391687 is 78619346.

64391687 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 64391687 - 2⁴ = 64391671 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 (64391387) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1110173 + ... + 1110230.

It is an arithmetic number, because the mean of its divisors is an integer number (16653030).

Almost surely, 2^64391687 is an apocalyptic number.

64391687 is a deficient number, since it is larger than the sum of its proper divisors (2220433).

64391687 is a wasteful number, since it uses less digits than its factorization.

64391687 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2220432.

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

The square root of 64391687 is about 8024.4430959413. The cubic root of 64391687 is about 400.8143555209.

The spelling of 64391687 in words is "sixty-four million, three hundred ninety-one thousand, six hundred eighty-seven".