21400384 has 28 divisors (see below), whose sum is σ = 44704000. Its totient is φ = 10136448.

The previous prime is 21400381. The next prime is 21400387. The reversal of 21400384 is 48300412.

It is an interprime number because it is at equal distance from previous prime (21400381) and next prime (21400387).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21400381) 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, 7584 + ... + 10015.

Almost surely, 2^21400384 is an apocalyptic number.

It is an amenable number.

21400384 is an abundant number, since it is smaller than the sum of its proper divisors (23303616).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21400384 is a wasteful number, since it uses less digits than its factorization.

21400384 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17630 (or 17620 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 22.

The square root of 21400384 is about 4626.0549067213. The cubic root of 21400384 is about 277.6347704539.

Adding to 21400384 its reverse (48300412), we get a palindrome (69700796).

The spelling of 21400384 in words is "twenty-one million, four hundred thousand, three hundred eighty-four".