81292271 has 2 divisors, whose sum is σ = 81292272. Its totient is φ = 81292270.

The previous prime is 81292259. The next prime is 81292273. The reversal of 81292271 is 17229218.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81292271 is a prime.

Together with 81292273, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81292273) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40646135 + 40646136.

It is an arithmetic number, because the mean of its divisors is an integer number (40646136).

Almost surely, 2^81292271 is an apocalyptic number.

81292271 is a deficient number, since it is larger than the sum of its proper divisors (1).

81292271 is an equidigital number, since it uses as much as digits as its factorization.

81292271 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4032, while the sum is 32.

The square root of 81292271 is about 9016.2226569667. Note that the first 3 decimals coincide. The cubic root of 81292271 is about 433.1946510192.

The spelling of 81292271 in words is "eighty-one million, two hundred ninety-two thousand, two hundred seventy-one".