81816108979 has 8 divisors (see below), whose sum is σ = 89259287040. Its totient is φ = 74373822600.

The previous prime is 81816108877. The next prime is 81816108991. The reversal of 81816108979 is 97980161818.

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

It is not a de Polignac number, because 81816108979 - 2⁹ = 81816108467 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81816108679) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 23287 + ... + 405184.

It is an arithmetic number, because the mean of its divisors is an integer number (11157410880).

Almost surely, 2^81816108979 is an apocalyptic number.

81816108979 is a deficient number, since it is larger than the sum of its proper divisors (7443178061).

81816108979 is a wasteful number, since it uses less digits than its factorization.

81816108979 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 445841.

The product of its (nonzero) digits is 1741824, while the sum is 58.

The spelling of 81816108979 in words is "eighty-one billion, eight hundred sixteen million, one hundred eight thousand, nine hundred seventy-nine".