1231125421 has 2 divisors, whose sum is σ = 1231125422. Its totient is φ = 1231125420.

The previous prime is 1231125373. The next prime is 1231125437. The reversal of 1231125421 is 1245211321.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 857669796 + 373455625 = 29286^2 + 19325^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1231125421 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1231125392 and 1231125401.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1231120421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 615562710 + 615562711.

It is an arithmetic number, because the mean of its divisors is an integer number (615562711).

Almost surely, 2^1231125421 is an apocalyptic number.

It is an amenable number.

1231125421 is a deficient number, since it is larger than the sum of its proper divisors (1).

1231125421 is an equidigital number, since it uses as much as digits as its factorization.

1231125421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 480, while the sum is 22.

The square root of 1231125421 is about 35087.3968968916. The cubic root of 1231125421 is about 1071.7679512424.

Adding to 1231125421 its reverse (1245211321), we get a palindrome (2476336742).

The spelling of 1231125421 in words is "one billion, two hundred thirty-one million, one hundred twenty-five thousand, four hundred twenty-one".