215138291 has 2 divisors, whose sum is σ = 215138292. Its totient is φ = 215138290.

The previous prime is 215138279. The next prime is 215138299. The reversal of 215138291 is 192831512.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 215138291 - 2¹⁰ = 215137267 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (215138299) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 107569145 + 107569146.

It is an arithmetic number, because the mean of its divisors is an integer number (107569146).

Almost surely, 2^215138291 is an apocalyptic number.

215138291 is a deficient number, since it is larger than the sum of its proper divisors (1).

215138291 is an equidigital number, since it uses as much as digits as its factorization.

215138291 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4320, while the sum is 32.

The square root of 215138291 is about 14667.5932245205. The cubic root of 215138291 is about 599.2010579211.

The spelling of 215138291 in words is "two hundred fifteen million, one hundred thirty-eight thousand, two hundred ninety-one".