128212261 has 2 divisors, whose sum is σ = 128212262. Its totient is φ = 128212260.

The previous prime is 128212229. The next prime is 128212303. The reversal of 128212261 is 162212821.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 87329025 + 40883236 = 9345^2 + 6394^2 .

It is a cyclic number.

It is not a de Polignac number, because 128212261 - 2⁵ = 128212229 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (128212061) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64106130 + 64106131.

It is an arithmetic number, because the mean of its divisors is an integer number (64106131).

Almost surely, 2^128212261 is an apocalyptic number.

It is an amenable number.

128212261 is a deficient number, since it is larger than the sum of its proper divisors (1).

128212261 is an equidigital number, since it uses as much as digits as its factorization.

128212261 is an evil number, because the sum of its binary digits is even.

The product of its digits is 768, while the sum is 25.

The square root of 128212261 is about 11323.0853127582. The cubic root of 128212261 is about 504.2468412199.

The spelling of 128212261 in words is "one hundred twenty-eight million, two hundred twelve thousand, two hundred sixty-one".