21213622 has 4 divisors (see below), whose sum is σ = 31820436. Its totient is φ = 10606810.

The previous prime is 21213611. The next prime is 21213623. The reversal of 21213622 is 22631212.

It is a semiprime because it is the product of two primes.

It is a self number, because there is not a number n which added to its sum of digits gives 21213622.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21213623) 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 as a sum of consecutive naturals, namely, 5303404 + ... + 5303407.

It is an arithmetic number, because the mean of its divisors is an integer number (7955109).

Almost surely, 2^21213622 is an apocalyptic number.

21213622 is a deficient number, since it is larger than the sum of its proper divisors (10606814).

21213622 is a wasteful number, since it uses less digits than its factorization.

21213622 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10606813.

The product of its digits is 288, while the sum is 19.

The square root of 21213622 is about 4605.8247904149. The cubic root of 21213622 is about 276.8247663335.

Adding to 21213622 its reverse (22631212), we get a palindrome (43844834).

The spelling of 21213622 in words is "twenty-one million, two hundred thirteen thousand, six hundred twenty-two".