81166368 has 48 divisors (see below), whose sum is σ = 217607040. Its totient is φ = 26478336.

The previous prime is 81166367. The next prime is 81166391. The reversal of 81166368 is 86366118.

It is a tau number, because it is divible by the number of its divisors (48).

It is a super-2 number, since 2×81166368² = 13175958588622848, which contains 22 as substring.

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (81166361) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4483 + ... + 13506.

It is an arithmetic number, because the mean of its divisors is an integer number (4533480).

Almost surely, 2^81166368 is an apocalyptic number.

It is an amenable number.

81166368 is an abundant number, since it is smaller than the sum of its proper divisors (136440672).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81166368 is a wasteful number, since it uses less digits than its factorization.

81166368 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18049 (or 18041 counting only the distinct ones).

The product of its digits is 41472, while the sum is 39.

The square root of 81166368 is about 9009.2379255961. The cubic root of 81166368 is about 432.9708958920.

The spelling of 81166368 in words is "eighty-one million, one hundred sixty-six thousand, three hundred sixty-eight".