65531664 has 90 divisors (see below), whose sum is σ = 201639438. Its totient is φ = 19852800.

The previous prime is 65531633. The next prime is 65531681. The reversal of 65531664 is 46613556.

65531664 is a `hidden beast` number, since 65 + 531 + 6 + 64 = 666.

It can be written as a sum of positive squares in only one way, i.e., 54641664 + 10890000 = 7392^2 + 3300^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 15544 + ... + 19304.

Almost surely, 2^65531664 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 65531664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (100819719).

65531664 is an abundant number, since it is smaller than the sum of its proper divisors (136107774).

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

65531664 is a wasteful number, since it uses less digits than its factorization.

65531664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3797 (or 3777 counting only the distinct ones).

The product of its digits is 64800, while the sum is 36.

The square root of 65531664 is about 8095.1630002119. The cubic root of 65531664 is about 403.1658441399.

The spelling of 65531664 in words is "sixty-five million, five hundred thirty-one thousand, six hundred sixty-four".