81394118479 has 2 divisors, whose sum is σ = 81394118480. Its totient is φ = 81394118478.

The previous prime is 81394118419. The next prime is 81394118497. The reversal of 81394118479 is 97481149318.

It is a happy number.

Together with next prime (81394118497) 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 81394118479 - 2²¹ = 81392021327 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81394118419) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40697059239 + 40697059240.

It is an arithmetic number, because the mean of its divisors is an integer number (40697059240).

Almost surely, 2^81394118479 is an apocalyptic number.

81394118479 is a deficient number, since it is larger than the sum of its proper divisors (1).

81394118479 is an equidigital number, since it uses as much as digits as its factorization.

81394118479 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1741824, while the sum is 55.

The spelling of 81394118479 in words is "eighty-one billion, three hundred ninety-four million, one hundred eighteen thousand, four hundred seventy-nine".