81586800 has 180 divisors, whose sum is σ = 286939224. Its totient is φ = 21465600.

The previous prime is 81586789. The next prime is 81586801. The reversal of 81586800 is 868518.

It is a tau number, because it is divible by the number of its divisors (180).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81586801) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 471514 + ... + 471686.

Almost surely, 2^81586800 is an apocalyptic number.

81586800 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 81586800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (143469612).

81586800 is an abundant number, since it is smaller than the sum of its proper divisors (205352424).

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

81586800 is a wasteful number, since it uses less digits than its factorization.

81586800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 328 (or 314 counting only the distinct ones).

The product of its (nonzero) digits is 15360, while the sum is 36.

The square root of 81586800 is about 9032.5411706784. The cubic root of 81586800 is about 433.7171878165.

The spelling of 81586800 in words is "eighty-one million, five hundred eighty-six thousand, eight hundred".