1215266491 has 2 divisors, whose sum is σ = 1215266492. Its totient is φ = 1215266490.

The previous prime is 1215266477. The next prime is 1215266497. The reversal of 1215266491 is 1946625121.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1215266491 - 2⁹ = 1215265979 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1215266491.

It is not a weakly prime, because it can be changed into another prime (1215266497) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 607633245 + 607633246.

It is an arithmetic number, because the mean of its divisors is an integer number (607633246).

Almost surely, 2^1215266491 is an apocalyptic number.

1215266491 is a deficient number, since it is larger than the sum of its proper divisors (1).

1215266491 is an equidigital number, since it uses as much as digits as its factorization.

1215266491 is an evil number, because the sum of its binary digits is even.

The product of its digits is 25920, while the sum is 37.

The square root of 1215266491 is about 34860.6725551875. The cubic root of 1215266491 is about 1067.1460004632.

The spelling of 1215266491 in words is "one billion, two hundred fifteen million, two hundred sixty-six thousand, four hundred ninety-one".