81947674889 has 4 divisors (see below), whose sum is σ = 81953409024. Its totient is φ = 81941940756.

The previous prime is 81947674843. The next prime is 81947674891. The reversal of 81947674889 is 98847674918.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81947674889 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81947674829) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2845577 + ... + 2874230.

It is an arithmetic number, because the mean of its divisors is an integer number (20488352256).

Almost surely, 2^81947674889 is an apocalyptic number.

It is an amenable number.

81947674889 is a deficient number, since it is larger than the sum of its proper divisors (5734135).

81947674889 is a wasteful number, since it uses less digits than its factorization.

81947674889 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5734134.

The product of its digits is 195084288, while the sum is 71.

The spelling of 81947674889 in words is "eighty-one billion, nine hundred forty-seven million, six hundred seventy-four thousand, eight hundred eighty-nine".