81851292 has 36 divisors (see below), whose sum is σ = 210810600. Its totient is φ = 26768352.

The previous prime is 81851291. The next prime is 81851303. The reversal of 81851292 is 29215818.

It is a tau number, because it is divible by the number of its divisors (36).

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 (81851291) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 19542 + ... + 23357.

It is an arithmetic number, because the mean of its divisors is an integer number (5855850).

Almost surely, 2^81851292 is an apocalyptic number.

It is an amenable number.

81851292 is an abundant number, since it is smaller than the sum of its proper divisors (128959308).

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

81851292 is a wasteful number, since it uses less digits than its factorization.

81851292 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42962 (or 42957 counting only the distinct ones).

The product of its digits is 11520, while the sum is 36.

The square root of 81851292 is about 9047.1703863694. The cubic root of 81851292 is about 434.1853639866.

The spelling of 81851292 in words is "eighty-one million, eight hundred fifty-one thousand, two hundred ninety-two".