81912960 has 96 divisors (see below), whose sum is σ = 282875580. Its totient is φ = 21841920.

The previous prime is 81912947. The next prime is 81912983. The reversal of 81912960 is 6921918.

It can be written as a sum of positive squares in 2 ways, for example, as 81866304 + 46656 = 9048^2 + 216^2 .

It is a tau number, because it is divible by the number of its divisors (96).

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 11 ways as a sum of consecutive naturals, for example, 1351 + ... + 12870.

Almost surely, 2^81912960 is an apocalyptic number.

81912960 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 81912960, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (141437790).

81912960 is an abundant number, since it is smaller than the sum of its proper divisors (200962620).

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

81912960 is a wasteful number, since it uses less digits than its factorization.

81912960 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14246 (or 14231 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 36.

The square root of 81912960 is about 9050.5778821023. The cubic root of 81912960 is about 434.2943772180.

The spelling of 81912960 in words is "eighty-one million, nine hundred twelve thousand, nine hundred sixty".