81986898 has 24 divisors (see below), whose sum is σ = 190745712. Its totient is φ = 23424744.

The previous prime is 81986897. The next prime is 81986899. The reversal of 81986898 is 89868918.

It is an interprime number because it is at equal distance from previous prime (81986897) and next prime (81986899).

It is a Smith number, since the sum of its digits (57) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (81986893) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 139140 + ... + 139727.

It is an arithmetic number, because the mean of its divisors is an integer number (7947738).

Almost surely, 2^81986898 is an apocalyptic number.

81986898 is an abundant number, since it is smaller than the sum of its proper divisors (108758814).

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

81986898 is a wasteful number, since it uses less digits than its factorization.

81986898 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 278886 (or 278879 counting only the distinct ones).

The product of its digits is 1990656, while the sum is 57.

The square root of 81986898 is about 9054.6616723100. The cubic root of 81986898 is about 434.4250085653.

The spelling of 81986898 in words is "eighty-one million, nine hundred eighty-six thousand, eight hundred ninety-eight".