11121221081 has 2 divisors, whose sum is σ = 11121221082. Its totient is φ = 11121221080.

The previous prime is 11121221057. The next prime is 11121221093. The reversal of 11121221081 is 18012212111.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 5562773056 + 5558448025 = 74584^2 + 74555^2 .

It is a cyclic number.

It is not a de Polignac number, because 11121221081 - 2³⁰ = 10047479257 is a prime.

It is a super-2 number, since 2×11121221081² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (11121229081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5560610540 + 5560610541.

It is an arithmetic number, because the mean of its divisors is an integer number (5560610541).

Almost surely, 2^11121221081 is an apocalyptic number.

It is an amenable number.

11121221081 is a deficient number, since it is larger than the sum of its proper divisors (1).

11121221081 is an equidigital number, since it uses as much as digits as its factorization.

11121221081 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 64, while the sum is 20.

Adding to 11121221081 its reverse (18012212111), we get a palindrome (29133433192).

The spelling of 11121221081 in words is "eleven billion, one hundred twenty-one million, two hundred twenty-one thousand, eighty-one".