81899850 has 48 divisors (see below), whose sum is σ = 207451008. Its totient is φ = 21373440.

The previous prime is 81899827. The next prime is 81899869. The reversal of 81899850 is 5899818.

It is a self number, because there is not a number n which added to its sum of digits gives 81899850.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1242 + ... + 12858.

It is an arithmetic number, because the mean of its divisors is an integer number (4321896).

Almost surely, 2^81899850 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81899850, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (103725504).

81899850 is an abundant number, since it is smaller than the sum of its proper divisors (125551158).

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

81899850 is a wasteful number, since it uses less digits than its factorization.

81899850 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11679 (or 11674 counting only the distinct ones).

The product of its (nonzero) digits is 207360, while the sum is 48.

The square root of 81899850 is about 9049.8535899759. The cubic root of 81899850 is about 434.2712066760.

The spelling of 81899850 in words is "eighty-one million, eight hundred ninety-nine thousand, eight hundred fifty".