1231561205124 has 72 divisors (see below), whose sum is σ = 3211250380128. Its totient is φ = 366036744960.

The previous prime is 1231561205123. The next prime is 1231561205131. The reversal of 1231561205124 is 4215021651321.

It is not an unprimeable number, because it can be changed into a prime (1231561205123) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 8287942 + ... + 8435229.

It is an arithmetic number, because the mean of its divisors is an integer number (44600699724).

Almost surely, 2^{1231561205124} is an apocalyptic number.

It is an amenable number.

1231561205124 is an abundant number, since it is smaller than the sum of its proper divisors (1979689175004).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1231561205124 is a wasteful number, since it uses less digits than its factorization.

1231561205124 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16723233 (or 16723212 counting only the distinct ones).

The product of its (nonzero) digits is 14400, while the sum is 33.

Adding to 1231561205124 its reverse (4215021651321), we get a palindrome (5446582856445).

The spelling of 1231561205124 in words is "one trillion, two hundred thirty-one billion, five hundred sixty-one million, two hundred five thousand, one hundred twenty-four".