81280000 has 110 divisors (see below), whose sum is σ = 204634496. Its totient is φ = 32256000.

The previous prime is 81279983. The next prime is 81280037. The reversal of 81280000 is 8218.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 81280000.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 639937 + ... + 640063.

Almost surely, 2^81280000 is an apocalyptic number.

81280000 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 81280000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (102317248).

81280000 is an abundant number, since it is smaller than the sum of its proper divisors (123354496).

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

81280000 is an equidigital number, since it uses as much as digits as its factorization.

81280000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 167 (or 134 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 19.

The square root of 81280000 is about 9015.5421356677. The cubic root of 81280000 is about 433.1728531328.

Adding to 81280000 its reverse (8218), we get a palindrome (81288218).

It can be divided in two parts, 8 and 1280000, that multiplied together give a square (10240000 = 3200²).

The spelling of 81280000 in words is "eighty-one million, two hundred eighty thousand".