81801836 has 12 divisors (see below), whose sum is σ = 143396400. Its totient is φ = 40831440.

The previous prime is 81801833. The next prime is 81801851. The reversal of 81801836 is 63810818.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 81801796 and 81801805.

It is not an unprimeable number, because it can be changed into a prime (81801833) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 14675 + ... + 19466.

It is an arithmetic number, because the mean of its divisors is an integer number (11949700).

Almost surely, 2^81801836 is an apocalyptic number.

It is an amenable number.

81801836 is a deficient number, since it is larger than the sum of its proper divisors (61594564).

81801836 is a wasteful number, since it uses less digits than its factorization.

81801836 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34744 (or 34742 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 35.

The square root of 81801836 is about 9044.4367431035. The cubic root of 81801836 is about 434.0978988731.

The spelling of 81801836 in words is "eighty-one million, eight hundred one thousand, eight hundred thirty-six".