21222473 has 4 divisors (see below), whose sum is σ = 21332628. Its totient is φ = 21112320.

The previous prime is 21222469. The next prime is 21222479. The reversal of 21222473 is 37422212.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 14684224 + 6538249 = 3832^2 + 2557^2 .

It is a cyclic number.

It is not a de Polignac number, because 21222473 - 2² = 21222469 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21222479) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 54788 + ... + 55173.

It is an arithmetic number, because the mean of its divisors is an integer number (5333157).

Almost surely, 2^21222473 is an apocalyptic number.

It is an amenable number.

21222473 is a deficient number, since it is larger than the sum of its proper divisors (110155).

21222473 is a wasteful number, since it uses less digits than its factorization.

21222473 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 110154.

The product of its digits is 1344, while the sum is 23.

The square root of 21222473 is about 4606.7855387461. The cubic root of 21222473 is about 276.8632610221.

Adding to 21222473 its reverse (37422212), we get a palindrome (58644685).

The spelling of 21222473 in words is "twenty-one million, two hundred twenty-two thousand, four hundred seventy-three".