1215231491 has 2 divisors, whose sum is σ = 1215231492. Its totient is φ = 1215231490.

The previous prime is 1215231487. The next prime is 1215231551. The reversal of 1215231491 is 1941325121.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1215231491 - 2² = 1215231487 is a prime.

It is not a weakly prime, because it can be changed into another prime (1215231191) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 607615745 + 607615746.

It is an arithmetic number, because the mean of its divisors is an integer number (607615746).

Almost surely, 2^1215231491 is an apocalyptic number.

1215231491 is a deficient number, since it is larger than the sum of its proper divisors (1).

1215231491 is an equidigital number, since it uses as much as digits as its factorization.

1215231491 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2160, while the sum is 29.

The square root of 1215231491 is about 34860.1705532259. The cubic root of 1215231491 is about 1067.1357556681.

The spelling of 1215231491 in words is "one billion, two hundred fifteen million, two hundred thirty-one thousand, four hundred ninety-one".