81619798 has 24 divisors (see below), whose sum is σ = 133802928. Its totient is φ = 37119888.

The previous prime is 81619781. The next prime is 81619819. The reversal of 81619798 is 89791618.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 162015 + ... + 162517.

It is an arithmetic number, because the mean of its divisors is an integer number (5575122).

Almost surely, 2^81619798 is an apocalyptic number.

81619798 is a deficient number, since it is larger than the sum of its proper divisors (52183130).

81619798 is a wasteful number, since it uses less digits than its factorization.

81619798 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 676 (or 597 counting only the distinct ones).

The product of its digits is 217728, while the sum is 49.

The square root of 81619798 is about 9034.3676037673. The cubic root of 81619798 is about 433.7756526283.

The spelling of 81619798 in words is "eighty-one million, six hundred nineteen thousand, seven hundred ninety-eight".