1215131191 has 2 divisors, whose sum is σ = 1215131192. Its totient is φ = 1215131190.

The previous prime is 1215131131. The next prime is 1215131201. The reversal of 1215131191 is 1911315121.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1215131191 is a prime.

It is a super-2 number, since 2×1215131191² = 2953087622682156962, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1215131131) 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, 607565595 + 607565596.

It is an arithmetic number, because the mean of its divisors is an integer number (607565596).

Almost surely, 2^1215131191 is an apocalyptic number.

1215131191 is a deficient number, since it is larger than the sum of its proper divisors (1).

1215131191 is an equidigital number, since it uses as much as digits as its factorization.

1215131191 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 270, while the sum is 25.

The square root of 1215131191 is about 34858.7319189898. The cubic root of 1215131191 is about 1067.1063959228.

The spelling of 1215131191 in words is "one billion, two hundred fifteen million, one hundred thirty-one thousand, one hundred ninety-one".