81759829 has 2 divisors, whose sum is σ = 81759830. Its totient is φ = 81759828.

The previous prime is 81759827. The next prime is 81759857. The reversal of 81759829 is 92895718.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 62837329 + 18922500 = 7927^2 + 4350^2 .

It is a cyclic number.

It is not a de Polignac number, because 81759829 - 2¹ = 81759827 is a prime.

Together with 81759827, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81759827) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40879914 + 40879915.

It is an arithmetic number, because the mean of its divisors is an integer number (40879915).

Almost surely, 2^81759829 is an apocalyptic number.

It is an amenable number.

81759829 is a deficient number, since it is larger than the sum of its proper divisors (1).

81759829 is an equidigital number, since it uses as much as digits as its factorization.

81759829 is an evil number, because the sum of its binary digits is even.

The product of its digits is 362880, while the sum is 49.

The square root of 81759829 is about 9042.1141886176. The cubic root of 81759829 is about 434.0235799515.

The spelling of 81759829 in words is "eighty-one million, seven hundred fifty-nine thousand, eight hundred twenty-nine".