21384993 has 16 divisors (see below), whose sum is σ = 33075200. Its totient is φ = 12036816.

The previous prime is 21384991. The next prime is 21385057. The reversal of 21384993 is 39948312.

It is not a de Polignac number, because 21384993 - 2¹ = 21384991 is a prime.

It is a super-2 number, since 2×21384993² = 914635851220098, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21384991) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6193 + ... + 9006.

It is an arithmetic number, because the mean of its divisors is an integer number (2067200).

Almost surely, 2^21384993 is an apocalyptic number.

It is an amenable number.

21384993 is a deficient number, since it is larger than the sum of its proper divisors (11690207).

21384993 is a wasteful number, since it uses less digits than its factorization.

21384993 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15276.

The product of its digits is 46656, while the sum is 39.

The square root of 21384993 is about 4624.3910950524. The cubic root of 21384993 is about 277.5681968580.

The spelling of 21384993 in words is "twenty-one million, three hundred eighty-four thousand, nine hundred ninety-three".