13421021405521 has 4 divisors (see below), whose sum is σ = 14127390953200. Its totient is φ = 12714651857844.

The previous prime is 13421021405503. The next prime is 13421021405573. The reversal of 13421021405521 is 12550412012431.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-13421021405521 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (13421021405321) 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, 353184773811 + ... + 353184773848.

It is an arithmetic number, because the mean of its divisors is an integer number (3531847738300).

Almost surely, 2^{13421021405521} is an apocalyptic number.

It is an amenable number.

13421021405521 is a deficient number, since it is larger than the sum of its proper divisors (706369547679).

13421021405521 is an equidigital number, since it uses as much as digits as its factorization.

13421021405521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 706369547678.

The product of its (nonzero) digits is 9600, while the sum is 31.

Adding to 13421021405521 its reverse (12550412012431), we get a palindrome (25971433417952).

The spelling of 13421021405521 in words is "thirteen trillion, four hundred twenty-one billion, twenty-one million, four hundred five thousand, five hundred twenty-one".