128641817 has 2 divisors, whose sum is σ = 128641818. Its totient is φ = 128641816.

The previous prime is 128641813. The next prime is 128641823. The reversal of 128641817 is 718146821.

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., 67551961 + 61089856 = 8219^2 + 7816^2 .

It is a cyclic number.

It is not a de Polignac number, because 128641817 - 2² = 128641813 is a prime.

It is a super-2 number, since 2×128641817² = 33097434162122978, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (128641811) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64320908 + 64320909.

It is an arithmetic number, because the mean of its divisors is an integer number (64320909).

Almost surely, 2^128641817 is an apocalyptic number.

It is an amenable number.

128641817 is a deficient number, since it is larger than the sum of its proper divisors (1).

128641817 is an equidigital number, since it uses as much as digits as its factorization.

128641817 is an evil number, because the sum of its binary digits is even.

The product of its digits is 21504, while the sum is 38.

The square root of 128641817 is about 11342.0376035349. The cubic root of 128641817 is about 504.8093480240.

The spelling of 128641817 in words is "one hundred twenty-eight million, six hundred forty-one thousand, eight hundred seventeen".