21222237 has 8 divisors (see below), whose sum is σ = 28317600. Its totient is φ = 14137520.

The previous prime is 21222211. The next prime is 21222251. The reversal of 21222237 is 73222212.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21222237 - 2¹⁴ = 21205853 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21222037) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6514 + ... + 9212.

It is an arithmetic number, because the mean of its divisors is an integer number (3539700).

Almost surely, 2^21222237 is an apocalyptic number.

It is an amenable number.

21222237 is a deficient number, since it is larger than the sum of its proper divisors (7095363).

21222237 is a wasteful number, since it uses less digits than its factorization.

21222237 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5323.

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

The square root of 21222237 is about 4606.7599242852. The cubic root of 21222237 is about 276.8622347519.

Adding to 21222237 its reverse (73222212), we get a palindrome (94444449).

The spelling of 21222237 in words is "twenty-one million, two hundred twenty-two thousand, two hundred thirty-seven".