81861158 has 8 divisors (see below), whose sum is σ = 129254520. Its totient is φ = 38776320.

The previous prime is 81861151. The next prime is 81861167. The reversal of 81861158 is 85116818.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a Harshad number since it is a multiple of its sum of digits (38), and also a Moran number because the ratio is a prime number: 2154241 = 81861158 / (8 + 1 + 8 + 6 + 1 + 1 + 5 + 8).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81861151) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 1077083 + ... + 1077158.

It is an arithmetic number, because the mean of its divisors is an integer number (16156815).

Almost surely, 2^81861158 is an apocalyptic number.

81861158 is a deficient number, since it is larger than the sum of its proper divisors (47393362).

81861158 is a wasteful number, since it uses less digits than its factorization.

81861158 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2154262.

The product of its digits is 15360, while the sum is 38.

The square root of 81861158 is about 9047.7156232941. The cubic root of 81861158 is about 434.2028082264.

The spelling of 81861158 in words is "eighty-one million, eight hundred sixty-one thousand, one hundred fifty-eight".