21239384 has 16 divisors (see below), whose sum is σ = 40116600. Its totient is φ = 10541632.

The previous prime is 21239381. The next prime is 21239429. The reversal of 21239384 is 48393212.

It is a happy number.

It is a super-2 number, since 2×21239384² = 902222865398912, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21239384.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21239381) 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, 8594 + ... + 10785.

Almost surely, 2^21239384 is an apocalyptic number.

It is an amenable number.

21239384 is a deficient number, since it is larger than the sum of its proper divisors (18877216).

21239384 is a wasteful number, since it uses less digits than its factorization.

21239384 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19522 (or 19518 counting only the distinct ones).

The product of its digits is 10368, while the sum is 32.

The square root of 21239384 is about 4608.6206179290. The cubic root of 21239384 is about 276.9367804393.

The spelling of 21239384 in words is "twenty-one million, two hundred thirty-nine thousand, three hundred eighty-four".