81878280 has 96 divisors (see below), whose sum is σ = 270043200. Its totient is φ = 19845760.

The previous prime is 81878261. The next prime is 81878311. The reversal of 81878280 is 8287818.

It is a happy number.

It is an unprimeable number.

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 23 ways as a sum of consecutive naturals, for example, 11701 + ... + 17339.

It is an arithmetic number, because the mean of its divisors is an integer number (2812950).

Almost surely, 2^81878280 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81878280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (135021600).

81878280 is an abundant number, since it is smaller than the sum of its proper divisors (188164920).

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

81878280 is a wasteful number, since it uses less digits than its factorization.

81878280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5675 (or 5660 counting only the distinct ones).

The product of its (nonzero) digits is 57344, while the sum is 42.

The square root of 81878280 is about 9048.6617795119. The cubic root of 81878280 is about 434.2330785947.

The spelling of 81878280 in words is "eighty-one million, eight hundred seventy-eight thousand, two hundred eighty".