81972745996 has 24 divisors (see below), whose sum is σ = 143776503360. Its totient is φ = 40893801552.

The previous prime is 81972745963. The next prime is 81972746021. The reversal of 81972745996 is 69954727918.

It is a happy number.

It is a super-2 number, since 2×81972745996² (a number of 23 digits) contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8654055 + ... + 8663521.

It is an arithmetic number, because the mean of its divisors is an integer number (5990687640).

Almost surely, 2^81972745996 is an apocalyptic number.

It is an amenable number.

81972745996 is a deficient number, since it is larger than the sum of its proper divisors (61803757364).

81972745996 is a wasteful number, since it uses less digits than its factorization.

81972745996 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14133 (or 14131 counting only the distinct ones).

The product of its digits is 68584320, while the sum is 67.

The spelling of 81972745996 in words is "eighty-one billion, nine hundred seventy-two million, seven hundred forty-five thousand, nine hundred ninety-six".