43664 has 10 divisors (see below), whose sum is σ = 84630. Its totient is φ = 21824.

The previous prime is 43661. The next prime is 43669. The reversal of 43664 is 46634.

It can be written as a sum of positive squares in only one way, i.e., 43264 + 400 = 208^2 + 20^2 .

It is a nialpdrome in base 4 and base 16.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 43664.

It is not an unprimeable number, because it can be changed into a prime (43661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1349 + ... + 1380.

It is an arithmetic number, because the mean of its divisors is an integer number (8463).

2⁴³⁶⁶⁴ is an apocalyptic number.

It is an amenable number.

43664 is a deficient number, since it is larger than the sum of its proper divisors (40966).

43664 is a wasteful number, since it uses less digits than its factorization.

43664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2737 (or 2731 counting only the distinct ones).

The product of its digits is 1728, while the sum is 23.

The square root of 43664 is about 208.9593261857. The cubic root of 43664 is about 35.2133902225.

It can be divided in two parts, 43 and 664, that added together give a palindrome (707).

The spelling of 43664 in words is "forty-three thousand, six hundred sixty-four".