21144233 has 16 divisors (see below), whose sum is σ = 23853312. Its totient is φ = 18576000.

The previous prime is 21144229. The next prime is 21144259. The reversal of 21144233 is 33244112.

It is a cyclic number.

It is not a de Polignac number, because 21144233 - 2² = 21144229 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21144203) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 77888 + ... + 78158.

It is an arithmetic number, because the mean of its divisors is an integer number (1490832).

Almost surely, 2^21144233 is an apocalyptic number.

It is an amenable number.

21144233 is a deficient number, since it is larger than the sum of its proper divisors (2709079).

21144233 is a wasteful number, since it uses less digits than its factorization.

21144233 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 496.

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

The square root of 21144233 is about 4598.2858762804. The cubic root of 21144233 is about 276.5226086696.

Adding to 21144233 its reverse (33244112), we get a palindrome (54388345).

It can be divided in two parts, 211 and 44233, that added together give a palindrome (44444).

The spelling of 21144233 in words is "twenty-one million, one hundred forty-four thousand, two hundred thirty-three".