21222642 has 16 divisors (see below), whose sum is σ = 48508992. Its totient is φ = 6063600.

The previous prime is 21222611. The next prime is 21222653. The reversal of 21222642 is 24622212.

It is a Harshad number since it is a multiple of its sum of digits (21).

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, 252609 + ... + 252692.

It is an arithmetic number, because the mean of its divisors is an integer number (3031812).

Almost surely, 2^21222642 is an apocalyptic number.

21222642 is an abundant number, since it is smaller than the sum of its proper divisors (27286350).

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

21222642 is a wasteful number, since it uses less digits than its factorization.

21222642 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 505313.

The product of its digits is 768, while the sum is 21.

The square root of 21222642 is about 4606.8038812174. The cubic root of 21222642 is about 276.8639959312.

Adding to 21222642 its reverse (24622212), we get a palindrome (45844854).

The spelling of 21222642 in words is "twenty-one million, two hundred twenty-two thousand, six hundred forty-two".