13531321421 has 4 divisors (see below), whose sum is σ = 13531886172. Its totient is φ = 13530756672.

The previous prime is 13531321387. The next prime is 13531321483. The reversal of 13531321421 is 12412313531.

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 7155298921 + 6376022500 = 84589^2 + 79850^2 .

It is a cyclic number.

It is not a de Polignac number, because 13531321421 - 2⁶ = 13531321357 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 (13531324421) 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, 244766 + ... + 294911.

It is an arithmetic number, because the mean of its divisors is an integer number (3382971543).

Almost surely, 2^13531321421 is an apocalyptic number.

It is an amenable number.

13531321421 is a deficient number, since it is larger than the sum of its proper divisors (564751).

13531321421 is an equidigital number, since it uses as much as digits as its factorization.

13531321421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 564750.

The product of its digits is 2160, while the sum is 26.

Adding to 13531321421 its reverse (12412313531), we get a palindrome (25943634952).

The spelling of 13531321421 in words is "thirteen billion, five hundred thirty-one million, three hundred twenty-one thousand, four hundred twenty-one".