81297888 has 96 divisors (see below), whose sum is σ = 245306880. Its totient is φ = 23093760.

The previous prime is 81297869. The next prime is 81297889. The reversal of 81297888 is 88879218.

It is a happy number.

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

It is a self number, because there is not a number n which added to its sum of digits gives 81297888.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81297889) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 208798 + ... + 209186.

It is an arithmetic number, because the mean of its divisors is an integer number (2555280).

Almost surely, 2^81297888 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81297888, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (122653440).

81297888 is an abundant number, since it is smaller than the sum of its proper divisors (164008992).

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

81297888 is a wasteful number, since it uses less digits than its factorization.

81297888 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 720 (or 712 counting only the distinct ones).

The product of its digits is 516096, while the sum is 51.

The square root of 81297888 is about 9016.5341456682. The cubic root of 81297888 is about 433.2046281805.

The spelling of 81297888 in words is "eighty-one million, two hundred ninety-seven thousand, eight hundred eighty-eight".