81586000 has 120 divisors (see below), whose sum is σ = 210046824. Its totient is φ = 30643200.

The previous prime is 81585997. The next prime is 81586003. The reversal of 81586000 is 68518.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (81585997) and next prime (81586003).

It can be written as a sum of positive squares in 4 ways, for example, as 21492496 + 60093504 = 4636^2 + 7752^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 81586000.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81586003) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 721944 + ... + 722056.

Almost surely, 2^81586000 is an apocalyptic number.

81586000 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 81586000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (105023412).

81586000 is an abundant number, since it is smaller than the sum of its proper divisors (128460824).

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

81586000 is a wasteful number, since it uses less digits than its factorization.

81586000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 174 (or 139 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 28.

The square root of 81586000 is about 9032.4968862436. The cubic root of 81586000 is about 433.7157702061.

The spelling of 81586000 in words is "eighty-one million, five hundred eighty-six thousand".