21222620 has 24 divisors (see below), whose sum is σ = 46914000. Its totient is φ = 8042112.

The previous prime is 21222611. The next prime is 21222653. The reversal of 21222620 is 2622212.

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, 27545 + ... + 28304.

It is an arithmetic number, because the mean of its divisors is an integer number (1954750).

Almost surely, 2^21222620 is an apocalyptic number.

21222620 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21222620 is an abundant number, since it is smaller than the sum of its proper divisors (25691380).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21222620 is a wasteful number, since it uses less digits than its factorization.

21222620 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55877 (or 55875 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 17.

The square root of 21222620 is about 4606.8014934442. The cubic root of 21222620 is about 276.8639002628.

Adding to 21222620 its reverse (2622212), we get a palindrome (23844832).

The spelling of 21222620 in words is "twenty-one million, two hundred twenty-two thousand, six hundred twenty".