81856236 has 48 divisors (see below), whose sum is σ = 238129920. Its totient is φ = 21261120.

The previous prime is 81856231. The next prime is 81856273. The reversal of 81856236 is 63265818.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 81856194 and 81856203.

It is not an unprimeable number, because it can be changed into a prime (81856231) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 43371 + ... + 45218.

It is an arithmetic number, because the mean of its divisors is an integer number (4961040).

Almost surely, 2^81856236 is an apocalyptic number.

It is an amenable number.

81856236 is an abundant number, since it is smaller than the sum of its proper divisors (156273684).

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

81856236 is a wasteful number, since it uses less digits than its factorization.

81856236 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 88614 (or 88612 counting only the distinct ones).

The product of its digits is 69120, while the sum is 39.

The square root of 81856236 is about 9047.4436168456. The cubic root of 81856236 is about 434.1941057310.

The spelling of 81856236 in words is "eighty-one million, eight hundred fifty-six thousand, two hundred thirty-six".