215221231 has 2 divisors, whose sum is σ = 215221232. Its totient is φ = 215221230.

The previous prime is 215221229. The next prime is 215221247. The reversal of 215221231 is 132122512.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 215221231 - 2¹ = 215221229 is a prime.

It is a super-2 number, since 2×215221231² = 92640356546310722, which contains 22 as substring.

Together with 215221229, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 215221199 and 215221208.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (215221211) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 107610615 + 107610616.

It is an arithmetic number, because the mean of its divisors is an integer number (107610616).

Almost surely, 2^215221231 is an apocalyptic number.

215221231 is a deficient number, since it is larger than the sum of its proper divisors (1).

215221231 is an equidigital number, since it uses as much as digits as its factorization.

215221231 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 240, while the sum is 19.

The square root of 215221231 is about 14670.4202734618. The cubic root of 215221231 is about 599.2780492529.

Adding to 215221231 its reverse (132122512), we get a palindrome (347343743).

The spelling of 215221231 in words is "two hundred fifteen million, two hundred twenty-one thousand, two hundred thirty-one".