128493257 has 6 divisors (see below), whose sum is σ = 135612378. Its totient is φ = 121730112.

The previous prime is 128493251. The next prime is 128493271. The reversal of 128493257 is 752394821.

It can be written as a sum of positive squares in only one way, i.e., 69572281 + 58920976 = 8341^2 + 7676^2 .

It is not a de Polignac number, because 128493257 - 2⁴ = 128493241 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (128493251) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 177608 + ... + 178329.

It is an arithmetic number, because the mean of its divisors is an integer number (22602063).

Almost surely, 2^128493257 is an apocalyptic number.

It is an amenable number.

128493257 is a deficient number, since it is larger than the sum of its proper divisors (7119121).

128493257 is an equidigital number, since it uses as much as digits as its factorization.

128493257 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 355975 (or 355956 counting only the distinct ones).

The product of its digits is 120960, while the sum is 41.

The square root of 128493257 is about 11335.4866238728. The cubic root of 128493257 is about 504.6149494327.

The spelling of 128493257 in words is "one hundred twenty-eight million, four hundred ninety-three thousand, two hundred fifty-seven".