21235229 has 4 divisors (see below), whose sum is σ = 21244476. Its totient is φ = 21225984.

The previous prime is 21235223. The next prime is 21235243. The reversal of 21235229 is 92253212.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 4507129 + 16728100 = 2123^2 + 4090^2 .

It is a cyclic number.

It is not a de Polignac number, because 21235229 - 2⁴ = 21235213 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21235198 and 21235207.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21235223) 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, 1757 + ... + 6749.

It is an arithmetic number, because the mean of its divisors is an integer number (5311119).

Almost surely, 2^21235229 is an apocalyptic number.

It is an amenable number.

21235229 is a deficient number, since it is larger than the sum of its proper divisors (9247).

21235229 is an equidigital number, since it uses as much as digits as its factorization.

21235229 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9246.

The product of its digits is 2160, while the sum is 26.

The square root of 21235229 is about 4608.1698102392. The cubic root of 21235229 is about 276.9187204779.

The spelling of 21235229 in words is "twenty-one million, two hundred thirty-five thousand, two hundred twenty-nine".