81913360 has 40 divisors (see below), whose sum is σ = 191534616. Its totient is φ = 32578560.

The previous prime is 81913343. The next prime is 81913379. The reversal of 81913360 is 6331918.

It can be written as a sum of positive squares in 4 ways, for example, as 5035536 + 76877824 = 2244^2 + 8768^2 .

It is a tau number, because it is divible by the number of its divisors (40).

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 7 ways as a sum of consecutive naturals, for example, 11652 + ... + 17308.

Almost surely, 2^81913360 is an apocalyptic number.

81913360 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 81913360, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (95767308).

81913360 is an abundant number, since it is smaller than the sum of its proper divisors (109621256).

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

81913360 is a wasteful number, since it uses less digits than its factorization.

81913360 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5851 (or 5845 counting only the distinct ones).

The product of its (nonzero) digits is 3888, while the sum is 31.

The square root of 81913360 is about 9050.5999801118. The cubic root of 81913360 is about 434.2950841370.

The spelling of 81913360 in words is "eighty-one million, nine hundred thirteen thousand, three hundred sixty".