64615521 has 16 divisors (see below), whose sum is σ = 91450944. Its totient is φ = 40441344.

The previous prime is 64615517. The next prime is 64615543. The reversal of 64615521 is 12551646.

It is not a de Polignac number, because 64615521 - 2² = 64615517 is a prime.

It is not an unprimeable number, because it can be changed into a prime (64615511) 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, 22461 + ... + 25173.

It is an arithmetic number, because the mean of its divisors is an integer number (5715684).

Almost surely, 2^64615521 is an apocalyptic number.

It is an amenable number.

64615521 is a deficient number, since it is larger than the sum of its proper divisors (26835423).

64615521 is a wasteful number, since it uses less digits than its factorization.

64615521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3200.

The product of its digits is 7200, while the sum is 30.

The square root of 64615521 is about 8038.3780080312. The cubic root of 64615521 is about 401.2782462816.

The spelling of 64615521 in words is "sixty-four million, six hundred fifteen thousand, five hundred twenty-one".