1231253121 has 16 divisors (see below), whose sum is σ = 1876805504. Its totient is φ = 703344384.

The previous prime is 1231253119. The next prime is 1231253137. The reversal of 1231253121 is 1213521321.

It is not a de Polignac number, because 1231253121 - 2¹ = 1231253119 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1231253161) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 73305 + ... + 88521.

It is an arithmetic number, because the mean of its divisors is an integer number (117300344).

Almost surely, 2^1231253121 is an apocalyptic number.

It is an amenable number.

1231253121 is a deficient number, since it is larger than the sum of its proper divisors (645552383).

1231253121 is a wasteful number, since it uses less digits than its factorization.

1231253121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19080.

The product of its digits is 360, while the sum is 21.

The square root of 1231253121 is about 35089.2165914259. The cubic root of 1231253121 is about 1071.8050067780.

Adding to 1231253121 its reverse (1213521321), we get a palindrome (2444774442).

The spelling of 1231253121 in words is "one billion, two hundred thirty-one million, two hundred fifty-three thousand, one hundred twenty-one".