21329229 has 16 divisors (see below), whose sum is σ = 30219200. Its totient is φ = 13343616.

The previous prime is 21329207. The next prime is 21329263. The reversal of 21329229 is 92292312.

It is a happy number.

It is not a de Polignac number, because 21329229 - 2¹¹ = 21327181 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21329196 and 21329205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21329299) 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 15 ways as a sum of consecutive naturals, for example, 4497 + ... + 7929.

It is an arithmetic number, because the mean of its divisors is an integer number (1888700).

Almost surely, 2^21329229 is an apocalyptic number.

It is an amenable number.

21329229 is a deficient number, since it is larger than the sum of its proper divisors (8889971).

21329229 is a wasteful number, since it uses less digits than its factorization.

21329229 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3564.

The product of its digits is 3888, while the sum is 30.

The square root of 21329229 is about 4618.3578250283. The cubic root of 21329229 is about 277.3267224383.

It can be divided in two parts, 2 and 1329229, that added together give a palindrome (1329231).

The spelling of 21329229 in words is "twenty-one million, three hundred twenty-nine thousand, two hundred twenty-nine".