128434861 has 2 divisors, whose sum is σ = 128434862. Its totient is φ = 128434860.

The previous prime is 128434853. The next prime is 128434877. The reversal of 128434861 is 168434821.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 91298025 + 37136836 = 9555^2 + 6094^2 .

It is an emirp because it is prime and its reverse (168434821) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 128434861 - 2³ = 128434853 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 128434861.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (128434841) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64217430 + 64217431.

It is an arithmetic number, because the mean of its divisors is an integer number (64217431).

Almost surely, 2^128434861 is an apocalyptic number.

It is an amenable number.

128434861 is a deficient number, since it is larger than the sum of its proper divisors (1).

128434861 is an equidigital number, since it uses as much as digits as its factorization.

128434861 is an evil number, because the sum of its binary digits is even.

The product of its digits is 36864, while the sum is 37.

The square root of 128434861 is about 11332.9105264270. The cubic root of 128434861 is about 504.5384941633.

The spelling of 128434861 in words is "one hundred twenty-eight million, four hundred thirty-four thousand, eight hundred sixty-one".