1231121231 has 2 divisors, whose sum is σ = 1231121232. Its totient is φ = 1231121230.

The previous prime is 1231121183. The next prime is 1231121263. The reversal of 1231121231 is 1321211321.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1231121231 is a prime.

It is a super-2 number, since 2×1231121231² = 3031318970837910722, which contains 22 as substring.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1201121231) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 615560615 + 615560616.

It is an arithmetic number, because the mean of its divisors is an integer number (615560616).

Almost surely, 2^1231121231 is an apocalyptic number.

1231121231 is a deficient number, since it is larger than the sum of its proper divisors (1).

1231121231 is an equidigital number, since it uses as much as digits as its factorization.

1231121231 is an evil number, because the sum of its binary digits is even.

The product of its digits is 72, while the sum is 17.

The square root of 1231121231 is about 35087.3371887922. The cubic root of 1231121231 is about 1071.7667353596.

Adding to 1231121231 its reverse (1321211321), we get a palindrome (2552332552).

The spelling of 1231121231 in words is "one billion, two hundred thirty-one million, one hundred twenty-one thousand, two hundred thirty-one".