21722223 has 4 divisors (see below), whose sum is σ = 28962968. Its totient is φ = 14481480.

The previous prime is 21722221. The next prime is 21722249. The reversal of 21722223 is 32222712.

It is a happy number.

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

It is not a de Polignac number, because 21722223 - 2¹ = 21722221 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21722223.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21722221) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3620368 + ... + 3620373.

It is an arithmetic number, because the mean of its divisors is an integer number (7240742).

Almost surely, 2^21722223 is an apocalyptic number.

21722223 is a deficient number, since it is larger than the sum of its proper divisors (7240745).

21722223 is an equidigital number, since it uses as much as digits as its factorization.

21722223 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7240744.

The product of its digits is 672, while the sum is 21.

The square root of 21722223 is about 4660.7105681430. The cubic root of 21722223 is about 279.0196283772.

Adding to 21722223 its reverse (32222712), we get a palindrome (53944935).

It can be divided in two parts, 21722 and 223, that added together give a triangular number (21945 = T₂₀₉).

The spelling of 21722223 in words is "twenty-one million, seven hundred twenty-two thousand, two hundred twenty-three".