64515989 has 4 divisors (see below), whose sum is σ = 67321056. Its totient is φ = 61710924.

The previous prime is 64515977. The next prime is 64516019. The reversal of 64515989 is 98951546.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 98951546 = 2 ⋅49475773.

It is a cyclic number.

It is not a de Polignac number, because 64515989 - 2⁴ = 64515973 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 (64512989) 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, 1402499 + ... + 1402544.

It is an arithmetic number, because the mean of its divisors is an integer number (16830264).

Almost surely, 2^64515989 is an apocalyptic number.

It is an amenable number.

64515989 is a deficient number, since it is larger than the sum of its proper divisors (2805067).

64515989 is a wasteful number, since it uses less digits than its factorization.

64515989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2805066.

The product of its digits is 388800, while the sum is 47.

The square root of 64515989 is about 8032.1845720825. The cubic root of 64515989 is about 401.0721010146.

The spelling of 64515989 in words is "sixty-four million, five hundred fifteen thousand, nine hundred eighty-nine".