81110291 has 4 divisors (see below), whose sum is σ = 83726784. Its totient is φ = 78493800.

The previous prime is 81110269. The next prime is 81110317. The reversal of 81110291 is 19201118.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19201118 = 2 ⋅9600559.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81110291 is a prime.

It is a super-2 number, since 2×81110291² = 13157758612209362, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81110231) 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 in 3 ways as a sum of consecutive naturals, for example, 1308200 + ... + 1308261.

It is an arithmetic number, because the mean of its divisors is an integer number (20931696).

Almost surely, 2^81110291 is an apocalyptic number.

81110291 is a deficient number, since it is larger than the sum of its proper divisors (2616493).

81110291 is a wasteful number, since it uses less digits than its factorization.

81110291 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2616492.

The product of its (nonzero) digits is 144, while the sum is 23.

The square root of 81110291 is about 9006.1251934447. The cubic root of 81110291 is about 432.8711612228.

The spelling of 81110291 in words is "eighty-one million, one hundred ten thousand, two hundred ninety-one".