81158188 has 24 divisors (see below), whose sum is σ = 147505680. Its totient is φ = 39041280.

The previous prime is 81158179. The next prime is 81158197. The reversal of 81158188 is 88185118.

It is an interprime number because it is at equal distance from previous prime (81158179) and next prime (81158197).

It is a self number, because there is not a number n which added to its sum of digits gives 81158188.

It is an unprimeable number.

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

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8583 + ... + 15361.

It is an arithmetic number, because the mean of its divisors is an integer number (6146070).

Almost surely, 2^81158188 is an apocalyptic number.

It is an amenable number.

81158188 is a deficient number, since it is larger than the sum of its proper divisors (66347492).

81158188 is a wasteful number, since it uses less digits than its factorization.

81158188 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6897 (or 6895 counting only the distinct ones).

The product of its digits is 20480, while the sum is 40.

The square root of 81158188 is about 9008.7839356930. The cubic root of 81158188 is about 432.9563503728.

The spelling of 81158188 in words is "eighty-one million, one hundred fifty-eight thousand, one hundred eighty-eight".