215318251 has 2 divisors, whose sum is σ = 215318252. Its totient is φ = 215318250.

The previous prime is 215318237. The next prime is 215318267. The reversal of 215318251 is 152813512.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-215318251 is a prime.

It is not a weakly prime, because it can be changed into another prime (215318231) 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, 107659125 + 107659126.

It is an arithmetic number, because the mean of its divisors is an integer number (107659126).

Almost surely, 2^215318251 is an apocalyptic number.

215318251 is a deficient number, since it is larger than the sum of its proper divisors (1).

215318251 is an equidigital number, since it uses as much as digits as its factorization.

215318251 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2400, while the sum is 28.

The square root of 215318251 is about 14673.7265546282. The cubic root of 215318251 is about 599.3680856333.

The spelling of 215318251 in words is "two hundred fifteen million, three hundred eighteen thousand, two hundred fifty-one".