128866823 has 2 divisors, whose sum is σ = 128866824. Its totient is φ = 128866822.

The previous prime is 128866811. The next prime is 128866849. The reversal of 128866823 is 328668821.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 128866823 - 2²⁶ = 61757959 is a prime.

It is a super-2 number, since 2×128866823² = 33213316140226658, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (128866853) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64433411 + 64433412.

It is an arithmetic number, because the mean of its divisors is an integer number (64433412).

Almost surely, 2^128866823 is an apocalyptic number.

128866823 is a deficient number, since it is larger than the sum of its proper divisors (1).

128866823 is an equidigital number, since it uses as much as digits as its factorization.

128866823 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 221184, while the sum is 44.

The square root of 128866823 is about 11351.9523871447. The cubic root of 128866823 is about 505.1034954367.

The spelling of 128866823 in words is "one hundred twenty-eight million, eight hundred sixty-six thousand, eight hundred twenty-three".