21423211 has 8 divisors (see below), whose sum is σ = 22100544. Its totient is φ = 20755200.

The previous prime is 21423169. The next prime is 21423221. The reversal of 21423211 is 11232412.

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

It is not a de Polignac number, because 21423211 - 2¹¹ = 21421163 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21423221) 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 7 ways as a sum of consecutive naturals, for example, 2491 + ... + 7003.

It is an arithmetic number, because the mean of its divisors is an integer number (2762568).

Almost surely, 2^21423211 is an apocalyptic number.

21423211 is a deficient number, since it is larger than the sum of its proper divisors (677333).

21423211 is a wasteful number, since it uses less digits than its factorization.

21423211 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4661.

The product of its digits is 96, while the sum is 16.

The square root of 21423211 is about 4628.5214701889. The cubic root of 21423211 is about 277.7334496316.

Adding to 21423211 its reverse (11232412), we get a palindrome (32655623).

The spelling of 21423211 in words is "twenty-one million, four hundred twenty-three thousand, two hundred eleven".