81898144 has 48 divisors (see below), whose sum is σ = 168249312. Its totient is φ = 39207168.

The previous prime is 81898127. The next prime is 81898169. The reversal of 81898144 is 44189818.

It is a Harshad number since it is a multiple of its sum of digits (43).

It is a self number, because there is not a number n which added to its sum of digits gives 81898144.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 72367 + ... + 73489.

It is an arithmetic number, because the mean of its divisors is an integer number (3505194).

Almost surely, 2^81898144 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 81898144, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (84124656).

81898144 is an abundant number, since it is smaller than the sum of its proper divisors (86351168).

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

81898144 is a wasteful number, since it uses less digits than its factorization.

81898144 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1229 (or 1221 counting only the distinct ones).

The product of its digits is 73728, while the sum is 43.

The square root of 81898144 is about 9049.7593338166. The cubic root of 81898144 is about 434.2681913191.

It can be divided in two parts, 8189814 and 4, that added together give a palindrome (8189818).

The spelling of 81898144 in words is "eighty-one million, eight hundred ninety-eight thousand, one hundred forty-four".