81881298 has 36 divisors (see below), whose sum is σ = 187253118. Its totient is φ = 25855200.

The previous prime is 81881291. The next prime is 81881329. The reversal of 81881298 is 89218818.

It can be written as a sum of positive squares in only one way, i.e., 74080449 + 7800849 = 8607^2 + 2793^2 .

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (81881291) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 198 + ... + 12798.

Almost surely, 2^81881298 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81881298, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (93626559).

81881298 is an abundant number, since it is smaller than the sum of its proper divisors (105371820).

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

81881298 is a wasteful number, since it uses less digits than its factorization.

81881298 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12647 (or 12625 counting only the distinct ones).

The product of its digits is 73728, while the sum is 45.

The square root of 81881298 is about 9048.8285429662. The cubic root of 81881298 is about 434.2384137472.

The spelling of 81881298 in words is "eighty-one million, eight hundred eighty-one thousand, two hundred ninety-eight".