81166355 has 4 divisors (see below), whose sum is σ = 97399632. Its totient is φ = 64933080.

The previous prime is 81166307. The next prime is 81166357. The reversal of 81166355 is 55366118.

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

It is not a de Polignac number, because 81166355 - 2¹⁶ = 81100819 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81166357) 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, 8116631 + ... + 8116640.

It is an arithmetic number, because the mean of its divisors is an integer number (24349908).

Almost surely, 2^81166355 is an apocalyptic number.

81166355 is a deficient number, since it is larger than the sum of its proper divisors (16233277).

81166355 is a wasteful number, since it uses less digits than its factorization.

81166355 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16233276.

The product of its digits is 21600, while the sum is 35.

The square root of 81166355 is about 9009.2372041145. The cubic root of 81166355 is about 432.9708727765.

The spelling of 81166355 in words is "eighty-one million, one hundred sixty-six thousand, three hundred fifty-five".