81855236 has 12 divisors (see below), whose sum is σ = 144209100. Its totient is φ = 40652640.

The previous prime is 81855227. The next prime is 81855269. The reversal of 81855236 is 63255818.

It can be written as a sum of positive squares in 2 ways, for example, as 50495236 + 31360000 = 7106^2 + 5600^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 81855236.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 68075 + ... + 69266.

It is an arithmetic number, because the mean of its divisors is an integer number (12017425).

Almost surely, 2^81855236 is an apocalyptic number.

It is an amenable number.

81855236 is a deficient number, since it is larger than the sum of its proper divisors (62353864).

81855236 is a wasteful number, since it uses less digits than its factorization.

81855236 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 137494 (or 137492 counting only the distinct ones).

The product of its digits is 57600, while the sum is 38.

The square root of 81855236 is about 9047.3883524474. The cubic root of 81855236 is about 434.1923376072.

The spelling of 81855236 in words is "eighty-one million, eight hundred fifty-five thousand, two hundred thirty-six".