81275911 has 4 divisors (see below), whose sum is σ = 82304800. Its totient is φ = 80247024.

The previous prime is 81275879. The next prime is 81275921. The reversal of 81275911 is 11957218.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 81275911 - 2⁵ = 81275879 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 (81275921) 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, 514326 + ... + 514483.

It is an arithmetic number, because the mean of its divisors is an integer number (20576200).

Almost surely, 2^81275911 is an apocalyptic number.

81275911 is a deficient number, since it is larger than the sum of its proper divisors (1028889).

81275911 is a wasteful number, since it uses less digits than its factorization.

81275911 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1028888.

The product of its digits is 5040, while the sum is 34.

The square root of 81275911 is about 9015.3153577676. The cubic root of 81275911 is about 433.1655890518.

The spelling of 81275911 in words is "eighty-one million, two hundred seventy-five thousand, nine hundred eleven".