81284800 has 84 divisors (see below), whose sum is σ = 202393296. Its totient is φ = 32128000.

The previous prime is 81284779. The next prime is 81284807. The reversal of 81284800 is 848218.

It is a super-2 number, since 2×81284800² = 13214437422080000, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81284807) 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 11 ways as a sum of consecutive naturals, for example, 161349 + ... + 161851.

It is an arithmetic number, because the mean of its divisors is an integer number (2409444).

Almost surely, 2^81284800 is an apocalyptic number.

81284800 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 81284800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (101196648).

81284800 is an abundant number, since it is smaller than the sum of its proper divisors (121108496).

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

81284800 is a wasteful number, since it uses less digits than its factorization.

81284800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 626 (or 611 counting only the distinct ones).

The product of its (nonzero) digits is 4096, while the sum is 31.

The square root of 81284800 is about 9015.8083386904. The cubic root of 81284800 is about 433.1813799896.

The spelling of 81284800 in words is "eighty-one million, two hundred eighty-four thousand, eight hundred".