13123311515221 has 4 divisors (see below), whose sum is σ = 13124267411500. Its totient is φ = 13122355618944.

The previous prime is 13123311515203. The next prime is 13123311515261. The reversal of 13123311515221 is 12251511332131.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 3554126087121 + 9569185428100 = 1885239^2 + 3093410^2 .

It is a cyclic number.

It is not a de Polignac number, because 13123311515221 - 2¹⁵ = 13123311482453 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13123311515261) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 477927546 + ... + 477955003.

It is an arithmetic number, because the mean of its divisors is an integer number (3281066852875).

Almost surely, 2^{13123311515221} is an apocalyptic number.

It is an amenable number.

13123311515221 is a deficient number, since it is larger than the sum of its proper divisors (955896279).

13123311515221 is an equidigital number, since it uses as much as digits as its factorization.

13123311515221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 955896278.

The product of its digits is 5400, while the sum is 31.

Adding to 13123311515221 its reverse (12251511332131), we get a palindrome (25374822847352).

The spelling of 13123311515221 in words is "thirteen trillion, one hundred twenty-three billion, three hundred eleven million, five hundred fifteen thousand, two hundred twenty-one".