81271245 has 32 divisors (see below), whose sum is σ = 142300800. Its totient is φ = 39280640.

The previous prime is 81271241. The next prime is 81271297. The reversal of 81271245 is 54217218.

It is not a de Polignac number, because 81271245 - 2² = 81271241 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81271241) 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 31 ways as a sum of consecutive naturals, for example, 73537 + ... + 74633.

It is an arithmetic number, because the mean of its divisors is an integer number (4446900).

Almost surely, 2^81271245 is an apocalyptic number.

It is an amenable number.

81271245 is a deficient number, since it is larger than the sum of its proper divisors (61029555).

81271245 is a wasteful number, since it uses less digits than its factorization.

81271245 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1565.

The product of its digits is 4480, while the sum is 30.

The square root of 81271245 is about 9015.0565722019. The cubic root of 81271245 is about 433.1572996366.

The spelling of 81271245 in words is "eighty-one million, two hundred seventy-one thousand, two hundred forty-five".