221311121 has 2 divisors, whose sum is σ = 221311122. Its totient is φ = 221311120.

The previous prime is 221311091. The next prime is 221311147. The reversal of 221311121 is 121113122.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 180606721 + 40704400 = 13439^2 + 6380^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-221311121 is a prime.

It is a super-2 number, since 2×221311121² = 97957224556553282, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 221311096 and 221311105.

It is not a weakly prime, because it can be changed into another prime (221311421) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110655560 + 110655561.

It is an arithmetic number, because the mean of its divisors is an integer number (110655561).

Almost surely, 2^221311121 is an apocalyptic number.

It is an amenable number.

221311121 is a deficient number, since it is larger than the sum of its proper divisors (1).

221311121 is an equidigital number, since it uses as much as digits as its factorization.

221311121 is an evil number, because the sum of its binary digits is even.

The product of its digits is 24, while the sum is 14.

The square root of 221311121 is about 14876.5291987076. The cubic root of 221311121 is about 604.8779399957.

Adding to 221311121 its reverse (121113122), we get a palindrome (342424243).

The spelling of 221311121 in words is "two hundred twenty-one million, three hundred eleven thousand, one hundred twenty-one".