81128269 has 2 divisors, whose sum is σ = 81128270. Its totient is φ = 81128268.

The previous prime is 81128263. The next prime is 81128273. The reversal of 81128269 is 96282118.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 49070025 + 32058244 = 7005^2 + 5662^2 .

It is a cyclic number.

It is not a de Polignac number, because 81128269 - 2³ = 81128261 is a prime.

It is a super-2 number, since 2×81128269² = 13163592061872722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81128261) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40564134 + 40564135.

It is an arithmetic number, because the mean of its divisors is an integer number (40564135).

Almost surely, 2^81128269 is an apocalyptic number.

It is an amenable number.

81128269 is a deficient number, since it is larger than the sum of its proper divisors (1).

81128269 is an equidigital number, since it uses as much as digits as its factorization.

81128269 is an evil number, because the sum of its binary digits is even.

The product of its digits is 13824, while the sum is 37.

The square root of 81128269 is about 9007.1232366389. The cubic root of 81128269 is about 432.9031406537.

The spelling of 81128269 in words is "eighty-one million, one hundred twenty-eight thousand, two hundred sixty-nine".