81939982 has 8 divisors (see below), whose sum is σ = 123010056. Its totient is φ = 40936632.

The previous prime is 81939971. The next prime is 81940003. The reversal of 81939982 is 28993918.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13488 + ... + 18595.

It is an arithmetic number, because the mean of its divisors is an integer number (15376257).

Almost surely, 2^81939982 is an apocalyptic number.

81939982 is a deficient number, since it is larger than the sum of its proper divisors (41070074).

81939982 is a wasteful number, since it uses less digits than its factorization.

81939982 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33362.

The product of its digits is 279936, while the sum is 49.

The square root of 81939982 is about 9052.0705918591. The cubic root of 81939982 is about 434.3421279542.

The spelling of 81939982 in words is "eighty-one million, nine hundred thirty-nine thousand, nine hundred eighty-two".