81198880 has 72 divisors (see below), whose sum is σ = 223173468. Its totient is φ = 27836928.

The previous prime is 81198877. The next prime is 81198899. The reversal of 81198880 is 8889118.

It can be written as a sum of positive squares in 2 ways, for example, as 80784144 + 414736 = 8988^2 + 644^2 .

It is a super-2 number, since 2×81198880² = 13186516226508800, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2662 + ... + 13018.

Almost surely, 2^81198880 is an apocalyptic number.

81198880 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 81198880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (111586734).

81198880 is an abundant number, since it is smaller than the sum of its proper divisors (141974588).

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

81198880 is a wasteful number, since it uses less digits than its factorization.

81198880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10386 (or 10371 counting only the distinct ones).

The product of its (nonzero) digits is 36864, while the sum is 43.

The square root of 81198880 is about 9011.0421150941. The cubic root of 81198880 is about 433.0286984483.

The spelling of 81198880 in words is "eighty-one million, one hundred ninety-eight thousand, eight hundred eighty".