128440397 has 2 divisors, whose sum is σ = 128440398. Its totient is φ = 128440396.

The previous prime is 128440379. The next prime is 128440427. The reversal of 128440397 is 793044821.

Together with previous prime (128440379) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 94264681 + 34175716 = 9709^2 + 5846^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-128440397 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 128440397.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (128440337) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64220198 + 64220199.

It is an arithmetic number, because the mean of its divisors is an integer number (64220199).

Almost surely, 2^128440397 is an apocalyptic number.

It is an amenable number.

128440397 is a deficient number, since it is larger than the sum of its proper divisors (1).

128440397 is an equidigital number, since it uses as much as digits as its factorization.

128440397 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 48384, while the sum is 38.

The square root of 128440397 is about 11333.1547682011. The cubic root of 128440397 is about 504.5457431946.

The spelling of 128440397 in words is "one hundred twenty-eight million, four hundred forty thousand, three hundred ninety-seven".