128456261 has 2 divisors, whose sum is σ = 128456262. Its totient is φ = 128456260.

The previous prime is 128456231. The next prime is 128456287. The reversal of 128456261 is 162654821.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 125305636 + 3150625 = 11194^2 + 1775^2 .

It is a cyclic number.

It is not a de Polignac number, because 128456261 - 2¹⁰ = 128455237 is a prime.

It is equal to p_7295408 and since 128456261 and 7295408 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (128456221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64228130 + 64228131.

It is an arithmetic number, because the mean of its divisors is an integer number (64228131).

Almost surely, 2^128456261 is an apocalyptic number.

It is an amenable number.

128456261 is a deficient number, since it is larger than the sum of its proper divisors (1).

128456261 is an equidigital number, since it uses as much as digits as its factorization.

128456261 is an evil number, because the sum of its binary digits is even.

The product of its digits is 23040, while the sum is 35.

The square root of 128456261 is about 11333.8546399713. The cubic root of 128456261 is about 504.5665149153.

The spelling of 128456261 in words is "one hundred twenty-eight million, four hundred fifty-six thousand, two hundred sixty-one".