215221243 has 4 divisors (see below), whose sum is σ = 215763760. Its totient is φ = 214678728.

The previous prime is 215221231. The next prime is 215221247. The reversal of 215221243 is 342122512.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 215221243 - 2⁵ = 215221211 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (215221247) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 270663 + ... + 271456.

It is an arithmetic number, because the mean of its divisors is an integer number (53940940).

Almost surely, 2^215221243 is an apocalyptic number.

215221243 is a deficient number, since it is larger than the sum of its proper divisors (542517).

215221243 is an equidigital number, since it uses as much as digits as its factorization.

215221243 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 542516.

The product of its digits is 960, while the sum is 22.

The square root of 215221243 is about 14670.4206824481. The cubic root of 215221243 is about 599.2780603908.

Adding to 215221243 its reverse (342122512), we get a palindrome (557343755).

The spelling of 215221243 in words is "two hundred fifteen million, two hundred twenty-one thousand, two hundred forty-three".