81994508699 has 8 divisors (see below), whose sum is σ = 82462536000. Its totient is φ = 81526592392.

The previous prime is 81994508663. The next prime is 81994508767. The reversal of 81994508699 is 99680549918.

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

It is a cyclic number.

It is not a de Polignac number, because 81994508699 - 2³⁶ = 13275031963 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81994508639) 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, 1792292 + ... + 1837470.

It is an arithmetic number, because the mean of its divisors is an integer number (10307817000).

Almost surely, 2^81994508699 is an apocalyptic number.

81994508699 is a deficient number, since it is larger than the sum of its proper divisors (468027301).

81994508699 is a wasteful number, since it uses less digits than its factorization.

81994508699 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55497.

The product of its (nonzero) digits is 50388480, while the sum is 68.

The spelling of 81994508699 in words is "eighty-one billion, nine hundred ninety-four million, five hundred eight thousand, six hundred ninety-nine".