43817981 has 2 divisors, whose sum is σ = 43817982. Its totient is φ = 43817980.

The previous prime is 43817929. The next prime is 43817999. The reversal of 43817981 is 18971834.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 30349081 + 13468900 = 5509^2 + 3670^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-43817981 is a prime.

It is a super-2 number, since 2×43817981² = 3840030917832722, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (43817681) 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 as a sum of consecutive naturals, namely, 21908990 + 21908991.

It is an arithmetic number, because the mean of its divisors is an integer number (21908991).

Almost surely, 2^43817981 is an apocalyptic number.

It is an amenable number.

43817981 is a deficient number, since it is larger than the sum of its proper divisors (1).

43817981 is an equidigital number, since it uses as much as digits as its factorization.

43817981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 48384, while the sum is 41.

The square root of 43817981 is about 6619.5151635146. The cubic root of 43817981 is about 352.5473497416.

The spelling of 43817981 in words is "forty-three million, eight hundred seventeen thousand, nine hundred eighty-one".