81288231 has 16 divisors (see below), whose sum is σ = 113046528. Its totient is φ = 51897600.

The previous prime is 81288227. The next prime is 81288257. The reversal of 81288231 is 13288218.

It is not a de Polignac number, because 81288231 - 2² = 81288227 is a prime.

It is a super-2 number, since 2×81288231² = 13215552998218722, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 81288192 and 81288201.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81288211) 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 15 ways as a sum of consecutive naturals, for example, 4516 + ... + 13526.

It is an arithmetic number, because the mean of its divisors is an integer number (7065408).

Almost surely, 2^81288231 is an apocalyptic number.

81288231 is a deficient number, since it is larger than the sum of its proper divisors (31758297).

81288231 is a wasteful number, since it uses less digits than its factorization.

81288231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9142.

The product of its digits is 6144, while the sum is 33.

The square root of 81288231 is about 9015.9986135758. The cubic root of 81288231 is about 433.1874747101.

The spelling of 81288231 in words is "eighty-one million, two hundred eighty-eight thousand, two hundred thirty-one".