1231125511 has 12 divisors (see below), whose sum is σ = 1546538896. Its totient is φ = 959317920.

The previous prime is 1231125449. The next prime is 1231125523. The reversal of 1231125511 is 1155211321.

It is not a de Polignac number, because 1231125511 - 2¹¹ = 1231123463 is a prime.

It is a super-2 number, since 2×1231125511² = 3031340047670022242, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1231125551) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 725910 + ... + 727603.

Almost surely, 2^1231125511 is an apocalyptic number.

1231125511 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1231125511 is a deficient number, since it is larger than the sum of its proper divisors (315413385).

1231125511 is a wasteful number, since it uses less digits than its factorization.

1231125511 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1453542 (or 1453531 counting only the distinct ones).

The product of its digits is 300, while the sum is 22.

The square root of 1231125511 is about 35087.3981794034. The cubic root of 1231125511 is about 1071.7679773592.

Adding to 1231125511 its reverse (1155211321), we get a palindrome (2386336832).

The spelling of 1231125511 in words is "one billion, two hundred thirty-one million, one hundred twenty-five thousand, five hundred eleven".