64556521 has 4 divisors (see below), whose sum is σ = 65930112. Its totient is φ = 63182932.

The previous prime is 64556519. The next prime is 64556533. The reversal of 64556521 is 12565546.

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 a cyclic number.

It is not a de Polignac number, because 64556521 - 2¹ = 64556519 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (64556501) 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, 686725 + ... + 686818.

It is an arithmetic number, because the mean of its divisors is an integer number (16482528).

Almost surely, 2^64556521 is an apocalyptic number.

It is an amenable number.

64556521 is a deficient number, since it is larger than the sum of its proper divisors (1373591).

64556521 is a wasteful number, since it uses less digits than its factorization.

64556521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1373590.

The product of its digits is 36000, while the sum is 34.

The square root of 64556521 is about 8034.7072753150. The cubic root of 64556521 is about 401.1560742618.

The spelling of 64556521 in words is "sixty-four million, five hundred fifty-six thousand, five hundred twenty-one".