81263447 has 2 divisors, whose sum is σ = 81263448. Its totient is φ = 81263446.

The previous prime is 81263443. The next prime is 81263449. The reversal of 81263447 is 74436218.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81263447 - 2² = 81263443 is a prime.

Together with 81263449, 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 (81263443) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40631723 + 40631724.

It is an arithmetic number, because the mean of its divisors is an integer number (40631724).

Almost surely, 2^81263447 is an apocalyptic number.

81263447 is a deficient number, since it is larger than the sum of its proper divisors (1).

81263447 is an equidigital number, since it uses as much as digits as its factorization.

81263447 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 32256, while the sum is 35.

The square root of 81263447 is about 9014.6240631543. The cubic root of 81263447 is about 433.1434453365.

The spelling of 81263447 in words is "eighty-one million, two hundred sixty-three thousand, four hundred forty-seven".