21421323 has 24 divisors (see below), whose sum is σ = 38578176. Its totient is φ = 11127600.

The previous prime is 21421319. The next prime is 21421333. The reversal of 21421323 is 32312412.

It is not a de Polignac number, because 21421323 - 2² = 21421319 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21421296 and 21421305.

It is not an unprimeable number, because it can be changed into a prime (21421333) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 14763 + ... + 16148.

It is an arithmetic number, because the mean of its divisors is an integer number (1607424).

Almost surely, 2^21421323 is an apocalyptic number.

21421323 is a deficient number, since it is larger than the sum of its proper divisors (17156853).

21421323 is a wasteful number, since it uses less digits than its factorization.

21421323 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30935 (or 30932 counting only the distinct ones).

The product of its digits is 288, while the sum is 18.

The square root of 21421323 is about 4628.3175128766. The cubic root of 21421323 is about 277.7252906282.

Adding to 21421323 its reverse (32312412), we get a palindrome (53733735).

The spelling of 21421323 in words is "twenty-one million, four hundred twenty-one thousand, three hundred twenty-three".