64518391 has 4 divisors (see below), whose sum is σ = 73735312. Its totient is φ = 55301472.

The previous prime is 64518323. The next prime is 64518397. The reversal of 64518391 is 19381546.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19381546 = 2 ⋅9690773.

It is a cyclic number.

It is not a de Polignac number, because 64518391 - 2⁹ = 64517879 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 64518391.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64518397) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4608450 + ... + 4608463.

It is an arithmetic number, because the mean of its divisors is an integer number (18433828).

Almost surely, 2^64518391 is an apocalyptic number.

64518391 is a deficient number, since it is larger than the sum of its proper divisors (9216921).

64518391 is an equidigital number, since it uses as much as digits as its factorization.

64518391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9216920.

The product of its digits is 25920, while the sum is 37.

The square root of 64518391 is about 8032.3340941472. The cubic root of 64518391 is about 401.0770784021.

The spelling of 64518391 in words is "sixty-four million, five hundred eighteen thousand, three hundred ninety-one".