81290880 has 192 divisors, whose sum is σ = 306465120. Its totient is φ = 19691520.

The previous prime is 81290879. The next prime is 81290893. The reversal of 81290880 is 8809218.

It is a tau number, because it is divible by the number of its divisors (192).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 62719 + ... + 64001.

Almost surely, 2^81290880 is an apocalyptic number.

81290880 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 81290880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (153232560).

81290880 is an abundant number, since it is smaller than the sum of its proper divisors (225174240).

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

81290880 is a wasteful number, since it uses less digits than its factorization.

81290880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1319 (or 1304 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 36.

The square root of 81290880 is about 9016.1455179029. The cubic root of 81290880 is about 433.1921801930.

The spelling of 81290880 in words is "eighty-one million, two hundred ninety thousand, eight hundred eighty".