81189798 has 8 divisors (see below), whose sum is σ = 162379608. Its totient is φ = 27063264.

The previous prime is 81189769. The next prime is 81189827. The reversal of 81189798 is 89798118.

It is an interprime number because it is at equal distance from previous prime (81189769) and next prime (81189827).

It is a sphenic number, since it is the product of 3 distinct primes.

81189798 is an admirable number.

It is a self number, because there is not a number n which added to its sum of digits gives 81189798.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6765811 + ... + 6765822.

It is an arithmetic number, because the mean of its divisors is an integer number (20297451).

Almost surely, 2^81189798 is an apocalyptic number.

81189798 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

81189798 is a wasteful number, since it uses less digits than its factorization.

81189798 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13531638.

The product of its digits is 290304, while the sum is 51.

The square root of 81189798 is about 9010.5381637281. The cubic root of 81189798 is about 433.0125532614.

It can be divided in two parts, 811 and 89798, that added together give a palindrome (90609).

The spelling of 81189798 in words is "eighty-one million, one hundred eighty-nine thousand, seven hundred ninety-eight".