128447261 has 2 divisors, whose sum is σ = 128447262. Its totient is φ = 128447260.

The previous prime is 128447251. The next prime is 128447279. The reversal of 128447261 is 162744821.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 112487236 + 15960025 = 10606^2 + 3995^2 .

It is a cyclic number.

It is not a de Polignac number, because 128447261 - 2⁶ = 128447197 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (128447251) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64223630 + 64223631.

It is an arithmetic number, because the mean of its divisors is an integer number (64223631).

Almost surely, 2^128447261 is an apocalyptic number.

It is an amenable number.

128447261 is a deficient number, since it is larger than the sum of its proper divisors (1).

128447261 is an equidigital number, since it uses as much as digits as its factorization.

128447261 is an evil number, because the sum of its binary digits is even.

The product of its digits is 21504, while the sum is 35.

The square root of 128447261 is about 11333.4575924561. The cubic root of 128447261 is about 504.5547308661.

The spelling of 128447261 in words is "one hundred twenty-eight million, four hundred forty-seven thousand, two hundred sixty-one".