64939521 has 4 divisors (see below), whose sum is σ = 86586032. Its totient is φ = 43293012.

The previous prime is 64939519. The next prime is 64939561. The reversal of 64939521 is 12593946.

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.

It is not a de Polignac number, because 64939521 - 2¹ = 64939519 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 64939521.

It is not an unprimeable number, because it can be changed into a prime (64939561) 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, 10823251 + ... + 10823256.

It is an arithmetic number, because the mean of its divisors is an integer number (21646508).

Almost surely, 2^64939521 is an apocalyptic number.

It is an amenable number.

64939521 is a deficient number, since it is larger than the sum of its proper divisors (21646511).

64939521 is a wasteful number, since it uses less digits than its factorization.

64939521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21646510.

The product of its digits is 58320, while the sum is 39.

The square root of 64939521 is about 8058.5061270685. The cubic root of 64939521 is about 401.9478348687.

The spelling of 64939521 in words is "sixty-four million, nine hundred thirty-nine thousand, five hundred twenty-one".