65643864 has 128 divisors (see below), whose sum is σ = 199342080. Its totient is φ = 17740800.

The previous prime is 65643827. The next prime is 65643871. The reversal of 65643864 is 46834656.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 106084 + ... + 106700.

It is an arithmetic number, because the mean of its divisors is an integer number (1557360).

Almost surely, 2^65643864 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 65643864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (99671040).

65643864 is an abundant number, since it is smaller than the sum of its proper divisors (133698216).

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

65643864 is a wasteful number, since it uses less digits than its factorization.

65643864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 681 (or 677 counting only the distinct ones).

The product of its digits is 414720, while the sum is 42.

The square root of 65643864 is about 8102.0901007086. The cubic root of 65643864 is about 403.3958063343.

The spelling of 65643864 in words is "sixty-five million, six hundred forty-three thousand, eight hundred sixty-four".