1215643291 has 2 divisors, whose sum is σ = 1215643292. Its totient is φ = 1215643290.

The previous prime is 1215643223. The next prime is 1215643309. The reversal of 1215643291 is 1923465121.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1215643291 - 2¹¹ = 1215641243 is a prime.

It is a super-2 number, since 2×1215643291² = 2955577221906621362, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1215643201) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 607821645 + 607821646.

It is an arithmetic number, because the mean of its divisors is an integer number (607821646).

Almost surely, 2^1215643291 is an apocalyptic number.

1215643291 is a deficient number, since it is larger than the sum of its proper divisors (1).

1215643291 is an equidigital number, since it uses as much as digits as its factorization.

1215643291 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 12960, while the sum is 34.

The square root of 1215643291 is about 34866.0765071150. The cubic root of 1215643291 is about 1067.2562805445.

The spelling of 1215643291 in words is "one billion, two hundred fifteen million, six hundred forty-three thousand, two hundred ninety-one".