81171773942 has 16 divisors (see below), whose sum is σ = 139155674112. Its totient is φ = 34786887720.

The previous prime is 81171773929. The next prime is 81171773953. The reversal of 81171773942 is 24937717118.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 607193 + ... + 728715.

It is an arithmetic number, because the mean of its divisors is an integer number (8697229632).

Almost surely, 2^81171773942 is an apocalyptic number.

81171773942 is a deficient number, since it is larger than the sum of its proper divisors (57983900170).

81171773942 is a wasteful number, since it uses less digits than its factorization.

81171773942 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 169243.

The product of its digits is 592704, while the sum is 50.

The spelling of 81171773942 in words is "eighty-one billion, one hundred seventy-one million, seven hundred seventy-three thousand, nine hundred forty-two".