81449479 has 2 divisors, whose sum is σ = 81449480. Its totient is φ = 81449478.

The previous prime is 81449437. The next prime is 81449497. The reversal of 81449479 is 97494418.

Together with next prime (81449497) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81449479 - 2⁷ = 81449351 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81449419) 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, 40724739 + 40724740.

It is an arithmetic number, because the mean of its divisors is an integer number (40724740).

Almost surely, 2^81449479 is an apocalyptic number.

81449479 is a deficient number, since it is larger than the sum of its proper divisors (1).

81449479 is an equidigital number, since it uses as much as digits as its factorization.

81449479 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 290304, while the sum is 46.

The square root of 81449479 is about 9024.9365094720. The cubic root of 81449479 is about 433.4737173692.

The spelling of 81449479 in words is "eighty-one million, four hundred forty-nine thousand, four hundred seventy-nine".