64516921 has 16 divisors (see below), whose sum is σ = 80593920. Its totient is φ = 50365440.

The previous prime is 64516891. The next prime is 64516927. The reversal of 64516921 is 12961546.

64516921 = 494² + 495² + ... + 679².

It is a cyclic number.

It is not a de Polignac number, because 64516921 - 2⁹ = 64516409 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (64516927) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5056 + ... + 12433.

It is an arithmetic number, because the mean of its divisors is an integer number (5037120).

Almost surely, 2^64516921 is an apocalyptic number.

It is an amenable number.

64516921 is a deficient number, since it is larger than the sum of its proper divisors (16076999).

64516921 is a wasteful number, since it uses less digits than its factorization.

64516921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17544.

The product of its digits is 12960, while the sum is 34.

The square root of 64516921 is about 8032.2425884681. The cubic root of 64516921 is about 401.0740323054.

The spelling of 64516921 in words is "sixty-four million, five hundred sixteen thousand, nine hundred twenty-one".