21321351403 has 4 divisors (see below), whose sum is σ = 23259656088. Its totient is φ = 19383046720.

The previous prime is 21321351349. The next prime is 21321351407. The reversal of 21321351403 is 30415312312.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 21321351403 - 2²⁹ = 20784480491 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21321351407) 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, 969152326 + ... + 969152347.

It is an arithmetic number, because the mean of its divisors is an integer number (5814914022).

Almost surely, 2^21321351403 is an apocalyptic number.

21321351403 is a deficient number, since it is larger than the sum of its proper divisors (1938304685).

21321351403 is a wasteful number, since it uses less digits than its factorization.

21321351403 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1938304684.

The product of its (nonzero) digits is 2160, while the sum is 25.

Adding to 21321351403 its reverse (30415312312), we get a palindrome (51736663715).

The spelling of 21321351403 in words is "twenty-one billion, three hundred twenty-one million, three hundred fifty-one thousand, four hundred three".