43981537 has 2 divisors, whose sum is σ = 43981538. Its totient is φ = 43981536.

The previous prime is 43981513. The next prime is 43981541. The reversal of 43981537 is 73518934.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 28740321 + 15241216 = 5361^2 + 3904^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-43981537 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 43981537.

It is not a weakly prime, because it can be changed into another prime (43981577) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21990768 + 21990769.

It is an arithmetic number, because the mean of its divisors is an integer number (21990769).

Almost surely, 2^43981537 is an apocalyptic number.

It is an amenable number.

43981537 is a deficient number, since it is larger than the sum of its proper divisors (1).

43981537 is an equidigital number, since it uses as much as digits as its factorization.

43981537 is an evil number, because the sum of its binary digits is even.

The product of its digits is 90720, while the sum is 40.

The square root of 43981537 is about 6631.8577336972. The cubic root of 43981537 is about 352.9854472142.

The spelling of 43981537 in words is "forty-three million, nine hundred eighty-one thousand, five hundred thirty-seven".