81881184 has 288 divisors, whose sum is σ = 289578240. Its totient is φ = 19768320.

The previous prime is 81881171. The next prime is 81881207. The reversal of 81881184 is 48118818.

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1544902 + ... + 1544954.

It is an arithmetic number, because the mean of its divisors is an integer number (1005480).

Almost surely, 2^81881184 is an apocalyptic number.

81881184 is a gapful number since it is divisible by the number (84) 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 81881184, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (144789120).

81881184 is an abundant number, since it is smaller than the sum of its proper divisors (207697056).

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

81881184 is a wasteful number, since it uses less digits than its factorization.

81881184 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 114 (or 95 counting only the distinct ones).

The product of its digits is 16384, while the sum is 39.

The square root of 81881184 is about 9048.8222438061. The cubic root of 81881184 is about 434.2382122230.

The spelling of 81881184 in words is "eighty-one million, eight hundred eighty-one thousand, one hundred eighty-four".