81166800 has 360 divisors, whose sum is σ = 314931232. Its totient is φ = 17740800.

The previous prime is 81166769. The next prime is 81166807. The reversal of 81166800 is 866118.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81166807) 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 71 ways as a sum of consecutive naturals, for example, 1887579 + ... + 1887621.

Almost surely, 2^81166800 is an apocalyptic number.

81166800 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81166800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (157465616).

81166800 is an abundant number, since it is smaller than the sum of its proper divisors (233764432).

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

81166800 is a wasteful number, since it uses less digits than its factorization.

81166800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 99 (or 77 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 30.

The square root of 81166800 is about 9009.2619009550. The cubic root of 81166800 is about 432.9716640390.

The spelling of 81166800 in words is "eighty-one million, one hundred sixty-six thousand, eight hundred".