21329993 has 16 divisors (see below), whose sum is σ = 23310720. Its totient is φ = 19455744.

The previous prime is 21329983. The next prime is 21329999. The reversal of 21329993 is 39992312.

It is a cyclic number.

It is not a de Polignac number, because 21329993 - 2⁶ = 21329929 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21329999) 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, 75230 + ... + 75512.

It is an arithmetic number, because the mean of its divisors is an integer number (1456920).

Almost surely, 2^21329993 is an apocalyptic number.

21329993 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

It is an amenable number.

21329993 is a deficient number, since it is larger than the sum of its proper divisors (1980727).

21329993 is a wasteful number, since it uses less digits than its factorization.

21329993 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 448.

The product of its digits is 26244, while the sum is 38.

The square root of 21329993 is about 4618.4405376707. The cubic root of 21329993 is about 277.3300336236.

It can be divided in two parts, 21329 and 993, that added together give a palindrome (22322).

The spelling of 21329993 in words is "twenty-one million, three hundred twenty-nine thousand, nine hundred ninety-three".