81125855 has 4 divisors (see below), whose sum is σ = 97351032. Its totient is φ = 64900680.

The previous prime is 81125851. The next prime is 81125857. The reversal of 81125855 is 55852118.

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

It is not a de Polignac number, because 81125855 - 2² = 81125851 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81125851) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8112581 + ... + 8112590.

It is an arithmetic number, because the mean of its divisors is an integer number (24337758).

Almost surely, 2^81125855 is an apocalyptic number.

81125855 is a deficient number, since it is larger than the sum of its proper divisors (16225177).

81125855 is a wasteful number, since it uses less digits than its factorization.

81125855 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16225176.

The product of its digits is 16000, while the sum is 35.

The square root of 81125855 is about 9006.9892305920. The cubic root of 81125855 is about 432.8988468830.

The spelling of 81125855 in words is "eighty-one million, one hundred twenty-five thousand, eight hundred fifty-five".