81985942 has 8 divisors (see below), whose sum is σ = 124196832. Its totient is φ = 40587000.

The previous prime is 81985933. The next prime is 81985973. The reversal of 81985942 is 24958918.

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

It is a junction number, because it is equal to n+sod(n) for n = 81985892 and 81985901.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 202734 + ... + 203137.

It is an arithmetic number, because the mean of its divisors is an integer number (15524604).

Almost surely, 2^81985942 is an apocalyptic number.

81985942 is a deficient number, since it is larger than the sum of its proper divisors (42210890).

81985942 is a wasteful number, since it uses less digits than its factorization.

81985942 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 405974.

The product of its digits is 207360, while the sum is 46.

The square root of 81985942 is about 9054.6088816690. The cubic root of 81985942 is about 434.4233200357.

The spelling of 81985942 in words is "eighty-one million, nine hundred eighty-five thousand, nine hundred forty-two".