64813521 has 16 divisors (see below), whose sum is σ = 89654400. Its totient is φ = 41599488.

The previous prime is 64813487. The next prime is 64813531. The reversal of 64813521 is 12531846.

It is not a de Polignac number, because 64813521 - 2⁷ = 64813393 is a prime.

It is not an unprimeable number, because it can be changed into a prime (64813531) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 37345 + ... + 39041.

It is an arithmetic number, because the mean of its divisors is an integer number (5603400).

Almost surely, 2^64813521 is an apocalyptic number.

It is an amenable number.

64813521 is a deficient number, since it is larger than the sum of its proper divisors (24840879).

64813521 is a wasteful number, since it uses less digits than its factorization.

64813521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2168.

The product of its digits is 5760, while the sum is 30.

The square root of 64813521 is about 8050.6845050592. The cubic root of 64813521 is about 401.6877045352.

The spelling of 64813521 in words is "sixty-four million, eight hundred thirteen thousand, five hundred twenty-one".