81866167 has 4 divisors (see below), whose sum is σ = 81914776. Its totient is φ = 81817560.

The previous prime is 81866153. The next prime is 81866171. The reversal of 81866167 is 76166818.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 81866167 - 2²³ = 73477559 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81866107) 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, 21684 + ... + 25177.

It is an arithmetic number, because the mean of its divisors is an integer number (20478694).

Almost surely, 2^81866167 is an apocalyptic number.

81866167 is a deficient number, since it is larger than the sum of its proper divisors (48609).

81866167 is a wasteful number, since it uses less digits than its factorization.

81866167 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 48608.

The product of its digits is 96768, while the sum is 43.

The square root of 81866167 is about 9047.9924292630. The cubic root of 81866167 is about 434.2116641867.

The spelling of 81866167 in words is "eighty-one million, eight hundred sixty-six thousand, one hundred sixty-seven".