81979443 has 48 divisors (see below), whose sum is σ = 146764800. Its totient is φ = 42939072.

The previous prime is 81979439. The next prime is 81979463. The reversal of 81979443 is 34497918.

It is not a de Polignac number, because 81979443 - 2² = 81979439 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81979463) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 162730 + ... + 163232.

It is an arithmetic number, because the mean of its divisors is an integer number (3057600).

Almost surely, 2^81979443 is an apocalyptic number.

81979443 is a deficient number, since it is larger than the sum of its proper divisors (64785357).

81979443 is a wasteful number, since it uses less digits than its factorization.

81979443 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 728 (or 725 counting only the distinct ones).

The product of its digits is 217728, while the sum is 45.

The square root of 81979443 is about 9054.2499965486. The cubic root of 81979443 is about 434.4118408654.

The spelling of 81979443 in words is "eighty-one million, nine hundred seventy-nine thousand, four hundred forty-three".