128256629 has 2 divisors, whose sum is σ = 128256630. Its totient is φ = 128256628.

The previous prime is 128256617. The next prime is 128256643. The reversal of 128256629 is 926652821.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 126000625 + 2256004 = 11225^2 + 1502^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-128256629 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (128256649) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64128314 + 64128315.

It is an arithmetic number, because the mean of its divisors is an integer number (64128315).

Almost surely, 2^128256629 is an apocalyptic number.

It is an amenable number.

128256629 is a deficient number, since it is larger than the sum of its proper divisors (1).

128256629 is an equidigital number, since it uses as much as digits as its factorization.

128256629 is an evil number, because the sum of its binary digits is even.

The product of its digits is 103680, while the sum is 41.

The square root of 128256629 is about 11325.0443266241. The cubic root of 128256629 is about 504.3049995777.

The spelling of 128256629 in words is "one hundred twenty-eight million, two hundred fifty-six thousand, six hundred twenty-nine".