128257 has 2 divisors, whose sum is σ = 128258. Its totient is φ = 128256.

The previous prime is 128239. The next prime is 128273. The reversal of 128257 is 752821.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 126736 + 1521 = 356^2 + 39^2 .

It is an emirp because it is prime and its reverse (752821) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-128257 is a prime.

128257 is a lucky number.

It is not a weakly prime, because it can be changed into another prime (128237) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64128 + 64129.

It is an arithmetic number, because the mean of its divisors is an integer number (64129).

2¹²⁸²⁵⁷ is an apocalyptic number.

It is an amenable number.

128257 is a deficient number, since it is larger than the sum of its proper divisors (1).

128257 is an equidigital number, since it uses as much as digits as its factorization.

128257 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1120, while the sum is 25.

The square root of 128257 is about 358.1298647139. The cubic root of 128257 is about 50.4305485835.

It can be divided in two parts, 128 and 257, that multiplied together give a triangular number (32896 = T₂₅₆).

The spelling of 128257 in words is "one hundred twenty-eight thousand, two hundred fifty-seven".