21403384 has 8 divisors (see below), whose sum is σ = 40131360. Its totient is φ = 10701688.

The previous prime is 21403337. The next prime is 21403399. The reversal of 21403384 is 48330412.

It is a tau number, because it is divible by the number of its divisors (8).

It is a congruent number.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 1337704 + ... + 1337719.

It is an arithmetic number, because the mean of its divisors is an integer number (5016420).

Almost surely, 2^21403384 is an apocalyptic number.

It is an amenable number.

21403384 is a deficient number, since it is larger than the sum of its proper divisors (18727976).

21403384 is a wasteful number, since it uses less digits than its factorization.

21403384 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2675429 (or 2675425 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 25.

The square root of 21403384 is about 4626.3791457251. The cubic root of 21403384 is about 277.6477432023.

Adding to 21403384 its reverse (48330412), we get a palindrome (69733796).

The spelling of 21403384 in words is "twenty-one million, four hundred three thousand, three hundred eighty-four".