81697529194 has 8 divisors (see below), whose sum is σ = 125153661888. Its totient is φ = 39979641900.

The previous prime is 81697529149. The next prime is 81697529209. The reversal of 81697529194 is 49192579618.

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

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 434561232 + ... + 434561419.

It is an arithmetic number, because the mean of its divisors is an integer number (15644207736).

Almost surely, 2^81697529194 is an apocalyptic number.

81697529194 is a deficient number, since it is larger than the sum of its proper divisors (43456132694).

81697529194 is a wasteful number, since it uses less digits than its factorization.

81697529194 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 869122700.

The product of its digits is 9797760, while the sum is 61.

The spelling of 81697529194 in words is "eighty-one billion, six hundred ninety-seven million, five hundred twenty-nine thousand, one hundred ninety-four".