221211313 has 8 divisors (see below), whose sum is σ = 223819848. Its totient is φ = 218609664.

The previous prime is 221211269. The next prime is 221211379. The reversal of 221211313 is 313112122.

It can be written as a sum of positive squares in 4 ways, for example, as 5184 + 221206129 = 72^2 + 14873^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-221211313 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221211383) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 91245 + ... + 93637.

It is an arithmetic number, because the mean of its divisors is an integer number (27977481).

Almost surely, 2^221211313 is an apocalyptic number.

It is an amenable number.

221211313 is a deficient number, since it is larger than the sum of its proper divisors (2608535).

221211313 is an equidigital number, since it uses as much as digits as its factorization.

221211313 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3443.

The product of its digits is 72, while the sum is 16.

The square root of 221211313 is about 14873.1742745118. The cubic root of 221211313 is about 604.7869960266.

Adding to 221211313 its reverse (313112122), we get a palindrome (534323435).

The spelling of 221211313 in words is "two hundred twenty-one million, two hundred eleven thousand, three hundred thirteen".