21430221 has 8 divisors (see below), whose sum is σ = 28895040. Its totient is φ = 14126112.

The previous prime is 21430193. The next prime is 21430229. The reversal of 21430221 is 12203412.

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

It is not a de Polignac number, because 21430221 - 2¹³ = 21422029 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21430221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21430229) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 39865 + ... + 40398.

It is an arithmetic number, because the mean of its divisors is an integer number (3611880).

Almost surely, 2^21430221 is an apocalyptic number.

It is an amenable number.

21430221 is a deficient number, since it is larger than the sum of its proper divisors (7464819).

21430221 is an equidigital number, since it uses as much as digits as its factorization.

21430221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80355.

The product of its (nonzero) digits is 96, while the sum is 15.

The square root of 21430221 is about 4629.2786695121. The cubic root of 21430221 is about 277.7637391957.

Adding to 21430221 its reverse (12203412), we get a palindrome (33633633).

The spelling of 21430221 in words is "twenty-one million, four hundred thirty thousand, two hundred twenty-one".