81111617 has 2 divisors, whose sum is σ = 81111618. Its totient is φ = 81111616.

The previous prime is 81111553. The next prime is 81111619. The reversal of 81111617 is 71611118.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 81072016 + 39601 = 9004^2 + 199^2 .

It is a cyclic number.

It is not a de Polignac number, because 81111617 - 2⁶ = 81111553 is a prime.

Together with 81111619, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (81111619) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40555808 + 40555809.

It is an arithmetic number, because the mean of its divisors is an integer number (40555809).

Almost surely, 2^81111617 is an apocalyptic number.

It is an amenable number.

81111617 is a deficient number, since it is larger than the sum of its proper divisors (1).

81111617 is an equidigital number, since it uses as much as digits as its factorization.

81111617 is an evil number, because the sum of its binary digits is even.

The product of its digits is 336, while the sum is 26.

The square root of 81111617 is about 9006.1988097088. The cubic root of 81111617 is about 432.8735200851.

The spelling of 81111617 in words is "eighty-one million, one hundred eleven thousand, six hundred seventeen".