81849768 has 128 divisors (see below), whose sum is σ = 274821120. Its totient is φ = 19618560.

The previous prime is 81849763. The next prime is 81849773. The reversal of 81849768 is 86794818.

It is an interprime number because it is at equal distance from previous prime (81849763) and next prime (81849773).

It is a self number, because there is not a number n which added to its sum of digits gives 81849768.

It is not an unprimeable number, because it can be changed into a prime (81849763) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 22321 + ... + 25727.

It is an arithmetic number, because the mean of its divisors is an integer number (2147040).

Almost surely, 2^81849768 is an apocalyptic number.

81849768 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 81849768, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (137410560).

81849768 is an abundant number, since it is smaller than the sum of its proper divisors (192971352).

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

81849768 is a wasteful number, since it uses less digits than its factorization.

81849768 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3447 (or 3443 counting only the distinct ones).

The product of its digits is 774144, while the sum is 51.

The square root of 81849768 is about 9047.0861607481. The cubic root of 81849768 is about 434.1826692517.

The spelling of 81849768 in words is "eighty-one million, eight hundred forty-nine thousand, seven hundred sixty-eight".