64445521 has 16 divisors (see below), whose sum is σ = 78264576. Its totient is φ = 51803136.

The previous prime is 64445503. The next prime is 64445531. The reversal of 64445521 is 12554446.

It is a happy number.

It is not a de Polignac number, because 64445521 - 2⁷ = 64445393 is a prime.

It is a super-2 number, since 2×64445521² = 8306450353922882, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (64445531) 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, 39300 + ... + 40906.

It is an arithmetic number, because the mean of its divisors is an integer number (4891536).

Almost surely, 2^64445521 is an apocalyptic number.

It is an amenable number.

64445521 is a deficient number, since it is larger than the sum of its proper divisors (13819055).

64445521 is a wasteful number, since it uses less digits than its factorization.

64445521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1968.

The product of its digits is 19200, while the sum is 31.

The square root of 64445521 is about 8027.7967712194. The cubic root of 64445521 is about 400.9260232978.

Adding to 64445521 its reverse (12554446), we get a palindrome (76999967).

The spelling of 64445521 in words is "sixty-four million, four hundred forty-five thousand, five hundred twenty-one".