128639807 has 2 divisors, whose sum is σ = 128639808. Its totient is φ = 128639806.

The previous prime is 128639783. The next prime is 128639813. The reversal of 128639807 is 708936821.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 128639807 - 2⁶ = 128639743 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (128639827) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64319903 + 64319904.

It is an arithmetic number, because the mean of its divisors is an integer number (64319904).

Almost surely, 2^128639807 is an apocalyptic number.

128639807 is a deficient number, since it is larger than the sum of its proper divisors (1).

128639807 is an equidigital number, since it uses as much as digits as its factorization.

128639807 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 145152, while the sum is 44.

The square root of 128639807 is about 11341.9489947716. The cubic root of 128639807 is about 504.8067188321.

The spelling of 128639807 in words is "one hundred twenty-eight million, six hundred thirty-nine thousand, eight hundred seven".