81835380 has 192 divisors, whose sum is σ = 290304000. Its totient is φ = 18944640.

The previous prime is 81835373. The next prime is 81835387. The reversal of 81835380 is 8353818.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (81835373) and next prime (81835387).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81835387) 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 63 ways as a sum of consecutive naturals, for example, 136321 + ... + 136919.

It is an arithmetic number, because the mean of its divisors is an integer number (1512000).

Almost surely, 2^81835380 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 81835380, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (145152000).

81835380 is an abundant number, since it is smaller than the sum of its proper divisors (208468620).

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

81835380 is a wasteful number, since it uses less digits than its factorization.

81835380 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 651 (or 643 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 36.

The square root of 81835380 is about 9046.2909526502. The cubic root of 81835380 is about 434.1572267592.

It can be divided in two parts, 81835 and 380, that added together give a triangular number (82215 = T₄₀₅).

The spelling of 81835380 in words is "eighty-one million, eight hundred thirty-five thousand, three hundred eighty".