264215221 has 2 divisors, whose sum is σ = 264215222. Its totient is φ = 264215220.

The previous prime is 264215219. The next prime is 264215249. The reversal of 264215221 is 122512462.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 183467025 + 80748196 = 13545^2 + 8986^2 .

It is a cyclic number.

It is not a de Polignac number, because 264215221 - 2¹ = 264215219 is a prime.

Together with 264215219, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (264215321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 132107610 + 132107611.

It is an arithmetic number, because the mean of its divisors is an integer number (132107611).

Almost surely, 2^264215221 is an apocalyptic number.

It is an amenable number.

264215221 is a deficient number, since it is larger than the sum of its proper divisors (1).

264215221 is an equidigital number, since it uses as much as digits as its factorization.

264215221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1920, while the sum is 25.

The square root of 264215221 is about 16254.6984284545. The cubic root of 264215221 is about 641.6811440897.

Adding to 264215221 its reverse (122512462), we get a palindrome (386727683).

The spelling of 264215221 in words is "two hundred sixty-four million, two hundred fifteen thousand, two hundred twenty-one".