1231211121 has 16 divisors (see below), whose sum is σ = 1879578624. Its totient is φ = 702256464.

The previous prime is 1231211119. The next prime is 1231211123. The reversal of 1231211121 is 1211121321.

It is an interprime number because it is at equal distance from previous prime (1231211119) and next prime (1231211123).

It is not a de Polignac number, because 1231211121 - 2¹ = 1231211119 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 1231211121.

It is not an unprimeable number, because it can be changed into a prime (1231211123) 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, 42105 + ... + 65078.

It is an arithmetic number, because the mean of its divisors is an integer number (117473664).

Almost surely, 2^1231211121 is an apocalyptic number.

It is an amenable number.

1231211121 is a deficient number, since it is larger than the sum of its proper divisors (648367503).

1231211121 is a wasteful number, since it uses less digits than its factorization.

1231211121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 107740.

The product of its digits is 24, while the sum is 15.

The square root of 1231211121 is about 35088.6181118607. The cubic root of 1231211121 is about 1071.7928196489.

Adding to 1231211121 its reverse (1211121321), we get a palindrome (2442332442).

The spelling of 1231211121 in words is "one billion, two hundred thirty-one million, two hundred eleven thousand, one hundred twenty-one".