21316406 has 8 divisors (see below), whose sum is σ = 33006144. Its totient is φ = 10314360.

The previous prime is 21316397. The next prime is 21316417. The reversal of 21316406 is 60461312.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 171845 + ... + 171968.

It is an arithmetic number, because the mean of its divisors is an integer number (4125768).

Almost surely, 2^21316406 is an apocalyptic number.

21316406 is a deficient number, since it is larger than the sum of its proper divisors (11689738).

21316406 is a wasteful number, since it uses less digits than its factorization.

21316406 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 343846.

The product of its (nonzero) digits is 864, while the sum is 23.

The square root of 21316406 is about 4616.9693522916. The cubic root of 21316406 is about 277.2711355963.

Adding to 21316406 its reverse (60461312), we get a palindrome (81777718).

The spelling of 21316406 in words is "twenty-one million, three hundred sixteen thousand, four hundred six".