64391389 has 4 divisors (see below), whose sum is σ = 64416924. Its totient is φ = 64365856.

The previous prime is 64391387. The next prime is 64391419. The reversal of 64391389 is 98319346.

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

It can be written as a sum of positive squares in 2 ways, for example, as 870489 + 63520900 = 933^2 + 7970^2 .

It is not a de Polignac number, because 64391389 - 2¹ = 64391387 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 polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8512 + ... + 14185.

It is an arithmetic number, because the mean of its divisors is an integer number (16104231).

Almost surely, 2^64391389 is an apocalyptic number.

It is an amenable number.

64391389 is a deficient number, since it is larger than the sum of its proper divisors (25535).

64391389 is a wasteful number, since it uses less digits than its factorization.

64391389 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25534.

The product of its digits is 139968, while the sum is 43.

The square root of 64391389 is about 8024.4245276531. The cubic root of 64391389 is about 400.8137372068.

The spelling of 64391389 in words is "sixty-four million, three hundred ninety-one thousand, three hundred eighty-nine".