21384535 has 12 divisors (see below), whose sum is σ = 26085528. Its totient is φ = 16827056.

The previous prime is 21384533. The next prime is 21384613. The reversal of 21384535 is 53548312.

It is not a de Polignac number, because 21384535 - 2¹ = 21384533 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21384497 and 21384506.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21384533) 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 11 ways as a sum of consecutive naturals, for example, 94092 + ... + 94318.

It is an arithmetic number, because the mean of its divisors is an integer number (2173794).

Almost surely, 2^21384535 is an apocalyptic number.

21384535 is a deficient number, since it is larger than the sum of its proper divisors (4700993).

21384535 is an frugal number, since it uses more digits than its factorization.

21384535 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 542 (or 315 counting only the distinct ones).

The product of its digits is 14400, while the sum is 31.

The square root of 21384535 is about 4624.3415747542. The cubic root of 21384535 is about 277.5662152948.

It can be divided in two parts, 213 and 84535, that added together give a palindrome (84748).

The spelling of 21384535 in words is "twenty-one million, three hundred eighty-four thousand, five hundred thirty-five".