81661196 has 12 divisors (see below), whose sum is σ = 144381048. Its totient is φ = 40409472.

The previous prime is 81661189. The next prime is 81661199. The reversal of 81661196 is 69116618.

It is a hoax number, since the sum of its digits (38) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (81661199) 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, 104846 + ... + 105621.

It is an arithmetic number, because the mean of its divisors is an integer number (12031754).

Almost surely, 2^81661196 is an apocalyptic number.

It is an amenable number.

81661196 is a deficient number, since it is larger than the sum of its proper divisors (62719852).

81661196 is a wasteful number, since it uses less digits than its factorization.

81661196 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 210568 (or 210566 counting only the distinct ones).

The product of its digits is 15552, while the sum is 38.

The square root of 81661196 is about 9036.6584532116. The cubic root of 81661196 is about 433.8489780131.

The spelling of 81661196 in words is "eighty-one million, six hundred sixty-one thousand, one hundred ninety-six".