13121155540 has 12 divisors (see below), whose sum is σ = 27554426676. Its totient is φ = 5248462208.

The previous prime is 13121155517. The next prime is 13121155547. The reversal of 13121155540 is 4555112131.

It can be written as a sum of positive squares in 2 ways, for example, as 7225680016 + 5895475524 = 85004^2 + 76782^2 .

It is a junction number, because it is equal to n+sod(n) for n = 13121155499 and 13121155508.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13121155547) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 328028869 + ... + 328028908.

It is an arithmetic number, because the mean of its divisors is an integer number (2296202223).

Almost surely, 2^13121155540 is an apocalyptic number.

13121155540 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

13121155540 is an abundant number, since it is smaller than the sum of its proper divisors (14433271136).

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

13121155540 is a wasteful number, since it uses less digits than its factorization.

13121155540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 656057786 (or 656057784 counting only the distinct ones).

The product of its (nonzero) digits is 3000, while the sum is 28.

Adding to 13121155540 its reverse (4555112131), we get a palindrome (17676267671).

The spelling of 13121155540 in words is "thirteen billion, one hundred twenty-one million, one hundred fifty-five thousand, five hundred forty".