21623222 has 4 divisors (see below), whose sum is σ = 32434836. Its totient is φ = 10811610.

The previous prime is 21623221. The next prime is 21623233. The reversal of 21623222 is 22232612.

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

It is a super-2 number, since 2×21623222² = 935127459322568, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21623194 and 21623203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21623221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5405804 + ... + 5405807.

It is an arithmetic number, because the mean of its divisors is an integer number (8108709).

Almost surely, 2^21623222 is an apocalyptic number.

21623222 is a deficient number, since it is larger than the sum of its proper divisors (10811614).

21623222 is a wasteful number, since it uses less digits than its factorization.

21623222 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10811613.

The product of its digits is 576, while the sum is 20.

The square root of 21623222 is about 4650.0776337605. The cubic root of 21623222 is about 278.5950970278.

Adding to 21623222 its reverse (22232612), we get a palindrome (43855834).

The spelling of 21623222 in words is "twenty-one million, six hundred twenty-three thousand, two hundred twenty-two".