81855292 has 12 divisors (see below), whose sum is σ = 143879400. Its totient is φ = 40746896.

The previous prime is 81855269. The next prime is 81855299. The reversal of 81855292 is 29255818.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81855299) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is an upside-down number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 44167 + ... + 45982.

It is an arithmetic number, because the mean of its divisors is an integer number (11989950).

Almost surely, 2^81855292 is an apocalyptic number.

It is an amenable number.

81855292 is a deficient number, since it is larger than the sum of its proper divisors (62024108).

81855292 is a wasteful number, since it uses less digits than its factorization.

81855292 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 90380 (or 90378 counting only the distinct ones).

The product of its digits is 57600, while the sum is 40.

The square root of 81855292 is about 9047.3914472626. The cubic root of 81855292 is about 434.1924366225.

The spelling of 81855292 in words is "eighty-one million, eight hundred fifty-five thousand, two hundred ninety-two".