12131555540 has 24 divisors (see below), whose sum is σ = 27435980040. Its totient is φ = 4479343488.

The previous prime is 12131555539. The next prime is 12131555549. The reversal of 12131555540 is 4555513121.

It can be written as a sum of positive squares in 4 ways, for example, as 186377104 + 11945178436 = 13652^2 + 109294^2 .

It is a junction number, because it is equal to n+sod(n) for n = 12131555497 and 12131555506.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12131555549) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 23329655 + ... + 23330174.

It is an arithmetic number, because the mean of its divisors is an integer number (1143165835).

Almost surely, 2^12131555540 is an apocalyptic number.

12131555540 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

12131555540 is an abundant number, since it is smaller than the sum of its proper divisors (15304424500).

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

12131555540 is a wasteful number, since it uses less digits than its factorization.

12131555540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46659851 (or 46659849 counting only the distinct ones).

The product of its (nonzero) digits is 15000, while the sum is 32.

The spelling of 12131555540 in words is "twelve billion, one hundred thirty-one million, five hundred fifty-five thousand, five hundred forty".