81420800 has 60 divisors (see below), whose sum is σ = 201758106. Its totient is φ = 32563200.

The previous prime is 81420799. The next prime is 81420809. The reversal of 81420800 is 802418.

It can be written as a sum of positive squares in 3 ways, for example, as 50239744 + 31181056 = 7088^2 + 5584^2 .

It is a hoax number, since the sum of its digits (23) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (81420809) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 9620 + ... + 15980.

Almost surely, 2^81420800 is an apocalyptic number.

81420800 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 81420800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (100879053).

81420800 is an abundant number, since it is smaller than the sum of its proper divisors (120337306).

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

81420800 is an equidigital number, since it uses as much as digits as its factorization.

81420800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6389 (or 6368 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 23.

The square root of 81420800 is about 9023.3474941399. The cubic root of 81420800 is about 433.4228348988.

The spelling of 81420800 in words is "eighty-one million, four hundred twenty thousand, eight hundred".