11111213021 has 2 divisors, whose sum is σ = 11111213022. Its totient is φ = 11111213020.

The previous prime is 11111213017. The next prime is 11111213027. The reversal of 11111213021 is 12031211111.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 5815740121 + 5295472900 = 76261^2 + 72770^2 .

It is an emirp because it is prime and its reverse (12031211111) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 11111213021 - 2² = 11111213017 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 11111212987 and 11111213005.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (11111213027) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5555606510 + 5555606511.

It is an arithmetic number, because the mean of its divisors is an integer number (5555606511).

Almost surely, 2^11111213021 is an apocalyptic number.

It is an amenable number.

11111213021 is a deficient number, since it is larger than the sum of its proper divisors (1).

11111213021 is an equidigital number, since it uses as much as digits as its factorization.

11111213021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 12, while the sum is 14.

Adding to 11111213021 its reverse (12031211111), we get a palindrome (23142424132).

The spelling of 11111213021 in words is "eleven billion, one hundred eleven million, two hundred thirteen thousand, twenty-one".