31111121 has 2 divisors, whose sum is σ = 31111122. Its totient is φ = 31111120.

The previous prime is 31111103. The next prime is 31111123. The reversal of 31111121 is 12111113.

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., 25654225 + 5456896 = 5065^2 + 2336^2 .

It is a cyclic number.

It is not a de Polignac number, because 31111121 - 2⁶ = 31111057 is a prime.

It is a Sophie Germain prime.

Together with 31111123, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (31111123) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15555560 + 15555561.

It is an arithmetic number, because the mean of its divisors is an integer number (15555561).

Almost surely, 2^31111121 is an apocalyptic number.

It is an amenable number.

31111121 is a deficient number, since it is larger than the sum of its proper divisors (1).

31111121 is an equidigital number, since it uses as much as digits as its factorization.

31111121 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6, while the sum is 11.

The square root of 31111121 is about 5577.7343966883. The cubic root of 31111121 is about 314.5129653445.

Adding to 31111121 its reverse (12111113), we get a palindrome (43222234).

It can be divided in two parts, 3111112 and 1, that added together give a palindrome (3111113).

The spelling of 31111121 in words is "thirty-one million, one hundred eleven thousand, one hundred twenty-one".