64641520 has 20 divisors (see below), whose sum is σ = 150291720. Its totient is φ = 25856576.

The previous prime is 64641509. The next prime is 64641539. The reversal of 64641520 is 2514646.

It is a tau number, because it is divible by the number of its divisors (20).

It is a super-2 number, since 2×64641520² = 8357052215820800, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 403930 + ... + 404089.

It is an arithmetic number, because the mean of its divisors is an integer number (7514586).

Almost surely, 2^64641520 is an apocalyptic number.

It is an amenable number.

64641520 is an abundant number, since it is smaller than the sum of its proper divisors (85650200).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

64641520 is a wasteful number, since it uses less digits than its factorization.

64641520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 808032 (or 808026 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 28.

The square root of 64641520 is about 8039.9950248741. The cubic root of 64641520 is about 401.3320591221.

The spelling of 64641520 in words is "sixty-four million, six hundred forty-one thousand, five hundred twenty".