43997661 has 20 divisors (see below), whose sum is σ = 66110044. Its totient is φ = 29160000.

The previous prime is 43997659. The next prime is 43997671. The reversal of 43997661 is 16679934.

It can be written as a sum of positive squares in 2 ways, for example, as 8820900 + 35176761 = 2970^2 + 5931^2 .

It is not a de Polignac number, because 43997661 - 2¹ = 43997659 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (43997641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 13161 + ... + 16161.

Almost surely, 2^43997661 is an apocalyptic number.

It is an amenable number.

43997661 is a deficient number, since it is larger than the sum of its proper divisors (22112383).

43997661 is a wasteful number, since it uses less digits than its factorization.

43997661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3194 (or 3185 counting only the distinct ones).

The product of its digits is 244944, while the sum is 45.

The square root of 43997661 is about 6633.0732696089. The cubic root of 43997661 is about 353.0285777515.

The spelling of 43997661 in words is "forty-three million, nine hundred ninety-seven thousand, six hundred sixty-one".