1231125431 has 4 divisors (see below), whose sum is σ = 1303544592. Its totient is φ = 1158706272.

The previous prime is 1231125421. The next prime is 1231125437. The reversal of 1231125431 is 1345211321.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1345211321 = 8821 ⋅152501.

It is a cyclic number.

It is not a de Polignac number, because 1231125431 - 2¹⁰ = 1231124407 is a prime.

It is a super-2 number, since 2×1231125431² = 3031339653709871522, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1231125397 and 1231125406.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1231125437) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 36209555 + ... + 36209588.

It is an arithmetic number, because the mean of its divisors is an integer number (325886148).

Almost surely, 2^1231125431 is an apocalyptic number.

1231125431 is a deficient number, since it is larger than the sum of its proper divisors (72419161).

1231125431 is an equidigital number, since it uses as much as digits as its factorization.

1231125431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72419160.

The product of its digits is 720, while the sum is 23.

The square root of 1231125431 is about 35087.3970393929. The cubic root of 1231125431 is about 1071.7679541443.

Adding to 1231125431 its reverse (1345211321), we get a palindrome (2576336752).

The spelling of 1231125431 in words is "one billion, two hundred thirty-one million, one hundred twenty-five thousand, four hundred thirty-one".