81898992 has 240 divisors, whose sum is σ = 282437280. Its totient is φ = 22643712.

The previous prime is 81898969. The next prime is 81899009. The reversal of 81898992 is 29989818.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1121868 + ... + 1121940.

It is an arithmetic number, because the mean of its divisors is an integer number (1176822).

Almost surely, 2^81898992 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 81898992, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (141218640).

81898992 is an abundant number, since it is smaller than the sum of its proper divisors (200538288).

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

81898992 is a wasteful number, since it uses less digits than its factorization.

81898992 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 157 (or 138 counting only the distinct ones).

The product of its digits is 746496, while the sum is 54.

The square root of 81898992 is about 9049.8061857699. The cubic root of 81898992 is about 434.2696901653.

The spelling of 81898992 in words is "eighty-one million, eight hundred ninety-eight thousand, nine hundred ninety-two".