64561520 has 40 divisors (see below), whose sum is σ = 150459120. Its totient is φ = 25763840.

The previous prime is 64561501. The next prime is 64561531. The reversal of 64561520 is 2516546.

It is a tau number, because it is divible by the number of its divisors (40).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 50651 + ... + 51909.

It is an arithmetic number, because the mean of its divisors is an integer number (3761478).

Almost surely, 2^64561520 is an apocalyptic number.

It is an amenable number.

64561520 is an abundant number, since it is smaller than the sum of its proper divisors (85897600).

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

64561520 is a wasteful number, since it uses less digits than its factorization.

64561520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1913 (or 1907 counting only the distinct ones).

The product of its (nonzero) digits is 7200, while the sum is 29.

The square root of 64561520 is about 8035.0183571663. The cubic root of 64561520 is about 401.1664286377.

The spelling of 64561520 in words is "sixty-four million, five hundred sixty-one thousand, five hundred twenty".