21313203421 has 16 divisors (see below), whose sum is σ = 22772620800. Its totient is φ = 19902859200.

The previous prime is 21313203409. The next prime is 21313203451. The reversal of 21313203421 is 12430231312.

It is a cyclic number.

It is not a de Polignac number, because 21313203421 - 2⁷ = 21313203293 is a prime.

It is a super-2 number, since 2×21313203421² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21313203392 and 21313203401.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21313203451) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1801995 + ... + 1813783.

It is an arithmetic number, because the mean of its divisors is an integer number (1423288800).

Almost surely, 2^21313203421 is an apocalyptic number.

It is an amenable number.

21313203421 is a deficient number, since it is larger than the sum of its proper divisors (1459417379).

21313203421 is a wasteful number, since it uses less digits than its factorization.

21313203421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13860.

The product of its (nonzero) digits is 864, while the sum is 22.

Adding to 21313203421 its reverse (12430231312), we get a palindrome (33743434733).

The spelling of 21313203421 in words is "twenty-one billion, three hundred thirteen million, two hundred three thousand, four hundred twenty-one".