64521816 has 32 divisors (see below), whose sum is σ = 161544240. Its totient is φ = 21475328.

The previous prime is 64521761. The next prime is 64521833. The reversal of 64521816 is 61812546.

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, 19000 + ... + 22136.

Almost surely, 2^64521816 is an apocalyptic number.

It is an amenable number.

64521816 is an abundant number, since it is smaller than the sum of its proper divisors (97022424).

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

64521816 is a wasteful number, since it uses less digits than its factorization.

64521816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4003 (or 3999 counting only the distinct ones).

The product of its digits is 11520, while the sum is 33.

The square root of 64521816 is about 8032.5472921110. The cubic root of 64521816 is about 401.0841754209.

The spelling of 64521816 in words is "sixty-four million, five hundred twenty-one thousand, eight hundred sixteen".