111431261 has 2 divisors, whose sum is σ = 111431262. Its totient is φ = 111431260.

The previous prime is 111431249. The next prime is 111431263. The reversal of 111431261 is 162134111.

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., 109725625 + 1705636 = 10475^2 + 1306^2 .

It is a cyclic number.

It is not a de Polignac number, because 111431261 - 2¹⁰ = 111430237 is a prime.

Together with 111431263, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (111431263) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 55715630 + 55715631.

It is an arithmetic number, because the mean of its divisors is an integer number (55715631).

Almost surely, 2^111431261 is an apocalyptic number.

It is an amenable number.

111431261 is a deficient number, since it is larger than the sum of its proper divisors (1).

111431261 is an equidigital number, since it uses as much as digits as its factorization.

111431261 is an evil number, because the sum of its binary digits is even.

The product of its digits is 144, while the sum is 20.

The square root of 111431261 is about 10556.1006531768. The cubic root of 111431261 is about 481.2111500431.

Adding to 111431261 its reverse (162134111), we get a palindrome (273565372).

The spelling of 111431261 in words is "one hundred eleven million, four hundred thirty-one thousand, two hundred sixty-one".