128372257 has 8 divisors (see below), whose sum is σ = 138349736. Its totient is φ = 118409472.

The previous prime is 128372239. The next prime is 128372261. The reversal of 128372257 is 752273821.

It can be written as a sum of positive squares in 4 ways, for example, as 26584336 + 101787921 = 5156^2 + 10089^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 128372257 - 2²³ = 119983649 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (128372857) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20323 + ... + 25879.

It is an arithmetic number, because the mean of its divisors is an integer number (17293717).

Almost surely, 2^128372257 is an apocalyptic number.

It is an amenable number.

128372257 is a deficient number, since it is larger than the sum of its proper divisors (9977479).

128372257 is a wasteful number, since it uses less digits than its factorization.

128372257 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7347.

The product of its digits is 47040, while the sum is 37.

The square root of 128372257 is about 11330.1481455451. The cubic root of 128372257 is about 504.4565038036.

The spelling of 128372257 in words is "one hundred twenty-eight million, three hundred seventy-two thousand, two hundred fifty-seven".