21233237 has 4 divisors (see below), whose sum is σ = 21685056. Its totient is φ = 20781420.

The previous prime is 21233213. The next prime is 21233239. The reversal of 21233237 is 73233212.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21233237 - 2¹⁶ = 21167701 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21233239) 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, 225839 + ... + 225932.

It is an arithmetic number, because the mean of its divisors is an integer number (5421264).

Almost surely, 2^21233237 is an apocalyptic number.

It is an amenable number.

21233237 is a deficient number, since it is larger than the sum of its proper divisors (451819).

21233237 is an equidigital number, since it uses as much as digits as its factorization.

21233237 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 451818.

The product of its digits is 1512, while the sum is 23.

The square root of 21233237 is about 4607.9536673018. The cubic root of 21233237 is about 276.9100612927.

Adding to 21233237 its reverse (73233212), we get a palindrome (94466449).

The spelling of 21233237 in words is "twenty-one million, two hundred thirty-three thousand, two hundred thirty-seven".