1255216121 has 2 divisors, whose sum is σ = 1255216122. Its totient is φ = 1255216120.

The previous prime is 1255216087. The next prime is 1255216129. The reversal of 1255216121 is 1216125521.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 762864400 + 492351721 = 27620^2 + 22189^2 .

It is a cyclic number.

It is not a de Polignac number, because 1255216121 - 2¹⁰ = 1255215097 is a prime.

It is not a weakly prime, because it can be changed into another prime (1255216129) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 627608060 + 627608061.

It is an arithmetic number, because the mean of its divisors is an integer number (627608061).

Almost surely, 2^1255216121 is an apocalyptic number.

It is an amenable number.

1255216121 is a deficient number, since it is larger than the sum of its proper divisors (1).

1255216121 is an equidigital number, since it uses as much as digits as its factorization.

1255216121 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1200, while the sum is 26.

The square root of 1255216121 is about 35429.0293544715. The cubic root of 1255216121 is about 1078.7136379206.

The spelling of 1255216121 in words is "one billion, two hundred fifty-five million, two hundred sixteen thousand, one hundred twenty-one".