404443981 has 2 divisors, whose sum is σ = 404443982. Its totient is φ = 404443980.

The previous prime is 404443973. The next prime is 404444021. The reversal of 404443981 is 189344404.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 297010756 + 107433225 = 17234^2 + 10365^2 .

It is a cyclic number.

It is not a de Polignac number, because 404443981 - 2³ = 404443973 is a prime.

It is a super-2 number, since 2×404443981² = 327149867534256722, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 404443981.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (404443951) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 202221990 + 202221991.

It is an arithmetic number, because the mean of its divisors is an integer number (202221991).

Almost surely, 2^404443981 is an apocalyptic number.

It is an amenable number.

404443981 is a deficient number, since it is larger than the sum of its proper divisors (1).

404443981 is an equidigital number, since it uses as much as digits as its factorization.

404443981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 55296, while the sum is 37.

The square root of 404443981 is about 20110.7926497192. The cubic root of 404443981 is about 739.5248843291.

The spelling of 404443981 in words is "four hundred four million, four hundred forty-three thousand, nine hundred eighty-one".