1221323011 has 2 divisors, whose sum is σ = 1221323012. Its totient is φ = 1221323010.

The previous prime is 1221323009. The next prime is 1221323041. The reversal of 1221323011 is 1103231221.

It is a weak prime.

It is an emirp because it is prime and its reverse (1103231221) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1221323011 - 2¹ = 1221323009 is a prime.

It is a super-2 number, since 2×1221323011² = 2983259794396212242, which contains 22 as substring.

Together with 1221323009, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (1221323041) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610661505 + 610661506.

It is an arithmetic number, because the mean of its divisors is an integer number (610661506).

Almost surely, 2^1221323011 is an apocalyptic number.

1221323011 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221323011 is an equidigital number, since it uses as much as digits as its factorization.

1221323011 is an evil number, because the sum of its binary digits is even.

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

The square root of 1221323011 is about 34947.4321088117. The cubic root of 1221323011 is about 1068.9158410453.

Adding to 1221323011 its reverse (1103231221), we get a palindrome (2324554232).

The spelling of 1221323011 in words is "one billion, two hundred twenty-one million, three hundred twenty-three thousand, eleven".