81819408 has 80 divisors (see below), whose sum is σ = 233485056. Its totient is φ = 24481920.

The previous prime is 81819379. The next prime is 81819443. The reversal of 81819408 is 80491818.

It is a happy number.

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 15 ways as a sum of consecutive naturals, for example, 42891 + ... + 44757.

Almost surely, 2^81819408 is an apocalyptic number.

81819408 is a gapful number since it is divisible by the number (88) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81819408, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (116742528).

81819408 is an abundant number, since it is smaller than the sum of its proper divisors (151665648).

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

81819408 is a wasteful number, since it uses less digits than its factorization.

81819408 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1972 (or 1966 counting only the distinct ones).

The product of its (nonzero) digits is 18432, while the sum is 39.

The square root of 81819408 is about 9045.4081168292. The cubic root of 81819408 is about 434.1289797654.

The spelling of 81819408 in words is "eighty-one million, eight hundred nineteen thousand, four hundred eight".