81479117 has 2 divisors, whose sum is σ = 81479118. Its totient is φ = 81479116.

The previous prime is 81479081. The next prime is 81479119. The reversal of 81479117 is 71197418.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 44342281 + 37136836 = 6659^2 + 6094^2 .

It is a cyclic number.

It is not a de Polignac number, because 81479117 - 2⁶ = 81479053 is a prime.

Together with 81479119, 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 (81479119) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40739558 + 40739559.

It is an arithmetic number, because the mean of its divisors is an integer number (40739559).

Almost surely, 2^81479117 is an apocalyptic number.

It is an amenable number.

81479117 is a deficient number, since it is larger than the sum of its proper divisors (1).

81479117 is an equidigital number, since it uses as much as digits as its factorization.

81479117 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 14112, while the sum is 38.

The square root of 81479117 is about 9026.5783661363. The cubic root of 81479117 is about 433.5262887554.

The spelling of 81479117 in words is "eighty-one million, four hundred seventy-nine thousand, one hundred seventeen".