81166456 has 64 divisors (see below), whose sum is σ = 182983680. Its totient is φ = 33022080.

The previous prime is 81166453. The next prime is 81166457. The reversal of 81166456 is 65466118.

It is a hoax number, since the sum of its digits (37) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (37).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81166451) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 88641 + ... + 89551.

It is an arithmetic number, because the mean of its divisors is an integer number (2859120).

Almost surely, 2^81166456 is an apocalyptic number.

81166456 is a gapful number since it is divisible by the number (86) formed by its first and last digit.

81166456 is the 4816-th nonagonal number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81166456, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (91491840).

81166456 is an abundant number, since it is smaller than the sum of its proper divisors (101817224).

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

81166456 is a wasteful number, since it uses less digits than its factorization.

81166456 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1004 (or 1000 counting only the distinct ones).

The product of its digits is 34560, while the sum is 37.

The square root of 81166456 is about 9009.2428094707. The cubic root of 81166456 is about 432.9710523666.

The spelling of 81166456 in words is "eighty-one million, one hundred sixty-six thousand, four hundred fifty-six".