13405502123221 has 4 divisors (see below), whose sum is σ = 14436694594252. Its totient is φ = 12374309652192.

The previous prime is 13405502123203. The next prime is 13405502123333. The reversal of 13405502123221 is 12232120550431.

It is a happy number.

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 6683460687121 + 6722041436100 = 2585239^2 + 2592690^2 .

It is a cyclic number.

It is not a de Polignac number, because 13405502123221 - 2¹⁹ = 13405501598933 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 (13405502129221) 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, 515596235496 + ... + 515596235521.

It is an arithmetic number, because the mean of its divisors is an integer number (3609173648563).

Almost surely, 2^{13405502123221} is an apocalyptic number.

It is an amenable number.

13405502123221 is a deficient number, since it is larger than the sum of its proper divisors (1031192471031).

13405502123221 is a wasteful number, since it uses less digits than its factorization.

13405502123221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1031192471030.

The product of its (nonzero) digits is 14400, while the sum is 31.

Adding to 13405502123221 its reverse (12232120550431), we get a palindrome (25637622673652).

The spelling of 13405502123221 in words is "thirteen trillion, four hundred five billion, five hundred two million, one hundred twenty-three thousand, two hundred twenty-one".