81166197 has 24 divisors (see below), whose sum is σ = 129301536. Its totient is φ = 45124128.

The previous prime is 81166193. The next prime is 81166199. The reversal of 81166197 is 79166118.

It is not a de Polignac number, because 81166197 - 2² = 81166193 is a prime.

It is a hoax number, since the sum of its digits (39) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81166193) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2023 + ... + 12900.

It is an arithmetic number, because the mean of its divisors is an integer number (5387564).

Almost surely, 2^81166197 is an apocalyptic number.

It is an amenable number.

81166197 is a deficient number, since it is larger than the sum of its proper divisors (48135339).

81166197 is a wasteful number, since it uses less digits than its factorization.

81166197 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14977 (or 14970 counting only the distinct ones).

The product of its digits is 18144, while the sum is 39.

The square root of 81166197 is about 9009.2284353323. The cubic root of 81166197 is about 432.9705918331.

The spelling of 81166197 in words is "eighty-one million, one hundred sixty-six thousand, one hundred ninety-seven".