21212254 has 16 divisors (see below), whose sum is σ = 36504576. Its totient is φ = 9055800.

The previous prime is 21212239. The next prime is 21212263. The reversal of 21212254 is 45221212.

It is a congruent number.

It is an unprimeable number.

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, 999 + ... + 6589.

It is an arithmetic number, because the mean of its divisors is an integer number (2281536).

Almost surely, 2^21212254 is an apocalyptic number.

21212254 is a deficient number, since it is larger than the sum of its proper divisors (15292322).

21212254 is a wasteful number, since it uses less digits than its factorization.

21212254 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5871.

The product of its digits is 320, while the sum is 19.

The square root of 21212254 is about 4605.6762804175. The cubic root of 21212254 is about 276.8188156850.

Adding to 21212254 its reverse (45221212), we get a palindrome (66433466).

The spelling of 21212254 in words is "twenty-one million, two hundred twelve thousand, two hundred fifty-four".