21406383 has 32 divisors (see below), whose sum is σ = 33912000. Its totient is φ = 13298688.

The previous prime is 21406367. The next prime is 21406391. The reversal of 21406383 is 38360412.

It is a happy number.

21406383 is a `hidden beast` number, since 21 + 4 + 0 + 638 + 3 = 666.

It is not a de Polignac number, because 21406383 - 2⁴ = 21406367 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21406883) 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 31 ways as a sum of consecutive naturals, for example, 68235 + ... + 68547.

It is an arithmetic number, because the mean of its divisors is an integer number (1059750).

Almost surely, 2^21406383 is an apocalyptic number.

21406383 is a deficient number, since it is larger than the sum of its proper divisors (12505617).

21406383 is a wasteful number, since it uses less digits than its factorization.

21406383 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 488 (or 482 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 27.

The square root of 21406383 is about 4626.7032539379. The cubic root of 21406383 is about 277.6607104150.

Adding to 21406383 its reverse (38360412), we get a palindrome (59766795).

The spelling of 21406383 in words is "twenty-one million, four hundred six thousand, three hundred eighty-three".