81862188 has 24 divisors (see below), whose sum is σ = 191229360. Its totient is φ = 27256320.

The previous prime is 81862181. The next prime is 81862201. The reversal of 81862188 is 88126818.

It is not an unprimeable number, because it can be changed into a prime (81862181) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8728 + ... + 15488.

It is an arithmetic number, because the mean of its divisors is an integer number (7967890).

Almost surely, 2^81862188 is an apocalyptic number.

It is an amenable number.

81862188 is an abundant number, since it is smaller than the sum of its proper divisors (109367172).

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

81862188 is a wasteful number, since it uses less digits than its factorization.

81862188 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7777 (or 7775 counting only the distinct ones).

The product of its digits is 49152, while the sum is 42.

The square root of 81862188 is about 9047.7725435601. The cubic root of 81862188 is about 434.2046293058.

The spelling of 81862188 in words is "eighty-one million, eight hundred sixty-two thousand, one hundred eighty-eight".