43957681 has 2 divisors, whose sum is σ = 43957682. Its totient is φ = 43957680.

The previous prime is 43957679. The next prime is 43957691. The reversal of 43957681 is 18675934.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 35892081 + 8065600 = 5991^2 + 2840^2 .

It is a cyclic number.

It is not a de Polignac number, because 43957681 - 2¹ = 43957679 is a prime.

It is a super-2 number, since 2×43957681² = 3864555437795522, which contains 22 as substring.

Together with 43957679, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (43957601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21978840 + 21978841.

It is an arithmetic number, because the mean of its divisors is an integer number (21978841).

Almost surely, 2^43957681 is an apocalyptic number.

It is an amenable number.

43957681 is a deficient number, since it is larger than the sum of its proper divisors (1).

43957681 is an equidigital number, since it uses as much as digits as its factorization.

43957681 is an evil number, because the sum of its binary digits is even.

The product of its digits is 181440, while the sum is 43.

The square root of 43957681 is about 6630.0588986826. The cubic root of 43957681 is about 352.9216147944.

The spelling of 43957681 in words is "forty-three million, nine hundred fifty-seven thousand, six hundred eighty-one".