21321413 has 4 divisors (see below), whose sum is σ = 21342048. Its totient is φ = 21300780.

The previous prime is 21321407. The next prime is 21321431. The reversal of 21321413 is 31412312.

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-21321413 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21321391 and 21321400.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21321493) 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, 8681 + ... + 10862.

It is an arithmetic number, because the mean of its divisors is an integer number (5335512).

Almost surely, 2^21321413 is an apocalyptic number.

It is an amenable number.

21321413 is a deficient number, since it is larger than the sum of its proper divisors (20635).

21321413 is a wasteful number, since it uses less digits than its factorization.

21321413 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20634.

The product of its digits is 144, while the sum is 17.

The square root of 21321413 is about 4617.5115592709. The cubic root of 21321413 is about 277.2928432565.

Adding to 21321413 its reverse (31412312), we get a palindrome (52733725).

The spelling of 21321413 in words is "twenty-one million, three hundred twenty-one thousand, four hundred thirteen".