64605521 has 4 divisors (see below), whose sum is σ = 64628544. Its totient is φ = 64582500.

The previous prime is 64605503. The next prime is 64605523. The reversal of 64605521 is 12550646.

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: 12550646 = 2 ⋅6275323.

It is a cyclic number.

It is not a de Polignac number, because 64605521 - 2¹⁰ = 64604497 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (64605523) 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, 6605 + ... + 13146.

It is an arithmetic number, because the mean of its divisors is an integer number (16157136).

Almost surely, 2^64605521 is an apocalyptic number.

It is an amenable number.

64605521 is a deficient number, since it is larger than the sum of its proper divisors (23023).

64605521 is a wasteful number, since it uses less digits than its factorization.

64605521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23022.

The product of its (nonzero) digits is 7200, while the sum is 29.

The square root of 64605521 is about 8037.7559679304. The cubic root of 64605521 is about 401.2575443954.

The spelling of 64605521 in words is "sixty-four million, six hundred five thousand, five hundred twenty-one".