81299479 has 2 divisors, whose sum is σ = 81299480. Its totient is φ = 81299478.

The previous prime is 81299459. The next prime is 81299489. The reversal of 81299479 is 97499218.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81299479 - 2²¹ = 79202327 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 (81299429) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40649739 + 40649740.

It is an arithmetic number, because the mean of its divisors is an integer number (40649740).

Almost surely, 2^81299479 is an apocalyptic number.

81299479 is a deficient number, since it is larger than the sum of its proper divisors (1).

81299479 is an equidigital number, since it uses as much as digits as its factorization.

81299479 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 326592, while the sum is 49.

The square root of 81299479 is about 9016.6223720415. The cubic root of 81299479 is about 433.2074541009.

The spelling of 81299479 in words is "eighty-one million, two hundred ninety-nine thousand, four hundred seventy-nine".