81100885 has 4 divisors (see below), whose sum is σ = 97321068. Its totient is φ = 64880704.

The previous prime is 81100853. The next prime is 81100909. The reversal of 81100885 is 58800118.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 33200644 + 47900241 = 5762^2 + 6921^2 .

It is a cyclic number.

It is not a de Polignac number, because 81100885 - 2⁵ = 81100853 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

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 3 ways as a sum of consecutive naturals, for example, 8110084 + ... + 8110093.

It is an arithmetic number, because the mean of its divisors is an integer number (24330267).

Almost surely, 2^81100885 is an apocalyptic number.

It is an amenable number.

81100885 is a deficient number, since it is larger than the sum of its proper divisors (16220183).

81100885 is a wasteful number, since it uses less digits than its factorization.

81100885 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16220182.

The product of its (nonzero) digits is 2560, while the sum is 31.

The square root of 81100885 is about 9005.6029781464. The cubic root of 81100885 is about 432.8544278609.

The spelling of 81100885 in words is "eighty-one million, one hundred thousand, eight hundred eighty-five".