81849158 has 4 divisors (see below), whose sum is σ = 122773740. Its totient is φ = 40924578.

The previous prime is 81849151. The next prime is 81849191. The reversal of 81849158 is 85194818.

It is a semiprime because it is the product of two primes.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81849151) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20462288 + ... + 20462291.

It is an arithmetic number, because the mean of its divisors is an integer number (30693435).

Almost surely, 2^81849158 is an apocalyptic number.

81849158 is a deficient number, since it is larger than the sum of its proper divisors (40924582).

81849158 is a wasteful number, since it uses less digits than its factorization.

81849158 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40924581.

The product of its digits is 92160, while the sum is 44.

The square root of 81849158 is about 9047.0524481734. The cubic root of 81849158 is about 434.1815906410.

The spelling of 81849158 in words is "eighty-one million, eight hundred forty-nine thousand, one hundred fifty-eight".