21424229 has 8 divisors (see below), whose sum is σ = 22595040. Its totient is φ = 20257776.

The previous prime is 21424223. The next prime is 21424241. The reversal of 21424229 is 92242412.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21424229 - 2⁴ = 21424213 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 = 21424198 and 21424207.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21424223) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 16139 + ... + 17415.

It is an arithmetic number, because the mean of its divisors is an integer number (2824380).

Almost surely, 2^21424229 is an apocalyptic number.

It is an amenable number.

21424229 is a deficient number, since it is larger than the sum of its proper divisors (1170811).

21424229 is a wasteful number, since it uses less digits than its factorization.

21424229 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2179.

The product of its digits is 2304, while the sum is 26.

The square root of 21424229 is about 4628.6314392053. The cubic root of 21424229 is about 277.7378487259.

The spelling of 21424229 in words is "twenty-one million, four hundred twenty-four thousand, two hundred twenty-nine".