81944019 has 12 divisors (see below), whose sum is σ = 119514096. Its totient is φ = 54098352.

The previous prime is 81943993. The next prime is 81944039. The reversal of 81944019 is 91044918.

It is not a de Polignac number, because 81944019 - 2⁵ = 81943987 is a prime.

It is a super-2 number, since 2×81944019² = 13429644499744722, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81944039) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 43272 + ... + 45125.

It is an arithmetic number, because the mean of its divisors is an integer number (9959508).

Almost surely, 2^81944019 is an apocalyptic number.

81944019 is a deficient number, since it is larger than the sum of its proper divisors (37570077).

81944019 is a wasteful number, since it uses less digits than its factorization.

81944019 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 88506 (or 88503 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 36.

The square root of 81944019 is about 9052.2935767683. The cubic root of 81944019 is about 434.3492608595.

The spelling of 81944019 in words is "eighty-one million, nine hundred forty-four thousand, nineteen".