21431326 has 20 divisors (see below), whose sum is σ = 37510992. Its totient is φ = 9182796.

The previous prime is 21431317. The next prime is 21431341. The reversal of 21431326 is 62313412.

It is a junction number, because it is equal to n+sod(n) for n = 21431297 and 21431306.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 2571 + ... + 7033.

Almost surely, 2^21431326 is an apocalyptic number.

21431326 is a deficient number, since it is larger than the sum of its proper divisors (16079666).

21431326 is an frugal number, since it uses more digits than its factorization.

21431326 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4493 (or 4472 counting only the distinct ones).

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

The square root of 21431326 is about 4629.3980170212. The cubic root of 21431326 is about 277.7685131962.

Adding to 21431326 its reverse (62313412), we get a palindrome (83744738).

The spelling of 21431326 in words is "twenty-one million, four hundred thirty-one thousand, three hundred twenty-six".