81738880 has 32 divisors (see below), whose sum is σ = 195408540. Its totient is φ = 32695296.

The previous prime is 81738869. The next prime is 81738887. The reversal of 81738880 is 8883718.

It can be written as a sum of positive squares in 2 ways, for example, as 78996544 + 2742336 = 8888^2 + 1656^2 .

It is a tau number, because it is divible by the number of its divisors (32).

It is not an unprimeable number, because it can be changed into a prime (81738887) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 63219 + ... + 64498.

Almost surely, 2^81738880 is an apocalyptic number.

81738880 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

81738880 is an abundant number, since it is smaller than the sum of its proper divisors (113669660).

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

81738880 is a wasteful number, since it uses less digits than its factorization.

81738880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 127736 (or 127724 counting only the distinct ones).

The product of its (nonzero) digits is 86016, while the sum is 43.

The square root of 81738880 is about 9040.9557016944. The cubic root of 81738880 is about 433.9865073991.

The spelling of 81738880 in words is "eighty-one million, seven hundred thirty-eight thousand, eight hundred eighty".