1131111281 has 2 divisors, whose sum is σ = 1131111282. Its totient is φ = 1131111280.

The previous prime is 1131111271. The next prime is 1131111283. The reversal of 1131111281 is 1821111311.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 640090000 + 491021281 = 25300^2 + 22159^2 .

It is a cyclic number.

It is not a de Polignac number, because 1131111281 - 2⁶ = 1131111217 is a prime.

It is a super-2 number, since 2×1131111281² = 2558825460010921922, which contains 22 as substring.

Together with 1131111283, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1131111283) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 565555640 + 565555641.

It is an arithmetic number, because the mean of its divisors is an integer number (565555641).

Almost surely, 2^1131111281 is an apocalyptic number.

It is an amenable number.

1131111281 is a deficient number, since it is larger than the sum of its proper divisors (1).

1131111281 is an equidigital number, since it uses as much as digits as its factorization.

1131111281 is an evil number, because the sum of its binary digits is even.

The product of its digits is 48, while the sum is 20.

The square root of 1131111281 is about 33631.9978740485. The cubic root of 1131111281 is about 1041.9217674892.

Adding to 1131111281 its reverse (1821111311), we get a palindrome (2952222592).

The spelling of 1131111281 in words is "one billion, one hundred thirty-one million, one hundred eleven thousand, two hundred eighty-one".