81758669 has 2 divisors, whose sum is σ = 81758670. Its totient is φ = 81758668.

The previous prime is 81758659. The next prime is 81758707. The reversal of 81758669 is 96685718.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 61418569 + 20340100 = 7837^2 + 4510^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81758669 is a prime.

It is a super-2 number, since 2×81758669² = 13368959913303122, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81758659) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40879334 + 40879335.

It is an arithmetic number, because the mean of its divisors is an integer number (40879335).

Almost surely, 2^81758669 is an apocalyptic number.

It is an amenable number.

81758669 is a deficient number, since it is larger than the sum of its proper divisors (1).

81758669 is an equidigital number, since it uses as much as digits as its factorization.

81758669 is an evil number, because the sum of its binary digits is even.

The product of its digits is 725760, while the sum is 50.

The square root of 81758669 is about 9042.0500440995. The cubic root of 81758669 is about 434.0215273146.

The spelling of 81758669 in words is "eighty-one million, seven hundred fifty-eight thousand, six hundred sixty-nine".