43991664 has 40 divisors (see below), whose sum is σ = 115349760. Its totient is φ = 14443968.

The previous prime is 43991653. The next prime is 43991681. The reversal of 43991664 is 46619934.

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, 3624 + ... + 10055.

It is an arithmetic number, because the mean of its divisors is an integer number (2883744).

Almost surely, 2^43991664 is an apocalyptic number.

It is an amenable number.

43991664 is an abundant number, since it is smaller than the sum of its proper divisors (71358096).

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

43991664 is a wasteful number, since it uses less digits than its factorization.

43991664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13757 (or 13751 counting only the distinct ones).

The product of its digits is 139968, while the sum is 42.

The square root of 43991664 is about 6632.6212013050. The cubic root of 43991664 is about 353.0125374399.

The spelling of 43991664 in words is "forty-three million, nine hundred ninety-one thousand, six hundred sixty-four".