11381221 has 2 divisors, whose sum is σ = 11381222. Its totient is φ = 11381220.

The previous prime is 11381219. The next prime is 11381233. The reversal of 11381221 is 12218311.

11381221 = 2385² + 2386².

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 5692996 + 5688225 = 2386^2 + 2385^2 .

It is a cyclic number.

It is not a de Polignac number, because 11381221 - 2¹ = 11381219 is a prime.

Together with 11381219, it forms a pair of twin primes.

It is a nialpdrome in base 15.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (11381261) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5690610 + 5690611.

It is an arithmetic number, because the mean of its divisors is an integer number (5690611).

Almost surely, 2^11381221 is an apocalyptic number.

11381221 is the 2386-th centered square number.

It is an amenable number.

11381221 is a deficient number, since it is larger than the sum of its proper divisors (1).

11381221 is an equidigital number, since it uses as much as digits as its factorization.

11381221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 96, while the sum is 19.

The square root of 11381221 is about 3373.6065271457. The cubic root of 11381221 is about 224.9380636106.

Adding to 11381221 its reverse (12218311), we get a palindrome (23599532).

The spelling of 11381221 in words is "eleven million, three hundred eighty-one thousand, two hundred twenty-one".