81137759 has 2 divisors, whose sum is σ = 81137760. Its totient is φ = 81137758.

The previous prime is 81137741. The next prime is 81137761. The reversal of 81137759 is 95773118.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81137759 - 2²⁰ = 80089183 is a prime.

Together with 81137761, 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 (81137789) 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, 40568879 + 40568880.

It is an arithmetic number, because the mean of its divisors is an integer number (40568880).

Almost surely, 2^81137759 is an apocalyptic number.

81137759 is a deficient number, since it is larger than the sum of its proper divisors (1).

81137759 is an equidigital number, since it uses as much as digits as its factorization.

81137759 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 52920, while the sum is 41.

The square root of 81137759 is about 9007.6500265052. The cubic root of 81137759 is about 432.9200196474.

The spelling of 81137759 in words is "eighty-one million, one hundred thirty-seven thousand, seven hundred fifty-nine".