128440999 has 2 divisors, whose sum is σ = 128441000. Its totient is φ = 128440998.

The previous prime is 128440997. The next prime is 128441003. The reversal of 128440999 is 999044821.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 128440999 - 2¹ = 128440997 is a prime.

Together with 128440997, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (128440997) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64220499 + 64220500.

It is an arithmetic number, because the mean of its divisors is an integer number (64220500).

Almost surely, 2^128440999 is an apocalyptic number.

128440999 is a deficient number, since it is larger than the sum of its proper divisors (1).

128440999 is an equidigital number, since it uses as much as digits as its factorization.

128440999 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 186624, while the sum is 46.

The square root of 128440999 is about 11333.1813274120. The cubic root of 128440999 is about 504.5465314618.

The spelling of 128440999 in words is "one hundred twenty-eight million, four hundred forty thousand, nine hundred ninety-nine".