128672657 has 2 divisors, whose sum is σ = 128672658. Its totient is φ = 128672656.

The previous prime is 128672633. The next prime is 128672669. The reversal of 128672657 is 756276821.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 71503936 + 57168721 = 8456^2 + 7561^2 .

It is an emirp because it is prime and its reverse (756276821) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 128672657 - 2¹⁶ = 128607121 is a prime.

It is not a weakly prime, because it can be changed into another prime (128672057) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64336328 + 64336329.

It is an arithmetic number, because the mean of its divisors is an integer number (64336329).

Almost surely, 2^128672657 is an apocalyptic number.

It is an amenable number.

128672657 is a deficient number, since it is larger than the sum of its proper divisors (1).

128672657 is an equidigital number, since it uses as much as digits as its factorization.

128672657 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 282240, while the sum is 44.

The square root of 128672657 is about 11343.3970661350. The cubic root of 128672657 is about 504.8496850277.

The spelling of 128672657 in words is "one hundred twenty-eight million, six hundred seventy-two thousand, six hundred fifty-seven".