81272489 has 2 divisors, whose sum is σ = 81272490. Its totient is φ = 81272488.

The previous prime is 81272453. The next prime is 81272491. The reversal of 81272489 is 98427218.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 69438889 + 11833600 = 8333^2 + 3440^2 .

It is a cyclic number.

It is not a de Polignac number, because 81272489 - 2¹⁶ = 81206953 is a prime.

Together with 81272491, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (81272419) 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 as a sum of consecutive naturals, namely, 40636244 + 40636245.

It is an arithmetic number, because the mean of its divisors is an integer number (40636245).

Almost surely, 2^81272489 is an apocalyptic number.

It is an amenable number.

81272489 is a deficient number, since it is larger than the sum of its proper divisors (1).

81272489 is an equidigital number, since it uses as much as digits as its factorization.

81272489 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 64512, while the sum is 41.

The square root of 81272489 is about 9015.1255676224. The cubic root of 81272489 is about 433.1595097046.

The spelling of 81272489 in words is "eighty-one million, two hundred seventy-two thousand, four hundred eighty-nine".