21140233 has 4 divisors (see below), whose sum is σ = 21822208. Its totient is φ = 20458260.

The previous prime is 21140213. The next prime is 21140237. The reversal of 21140233 is 33204112.

It is a happy number.

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 21140233 - 2⁵ = 21140201 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21140237) 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, 340941 + ... + 341002.

It is an arithmetic number, because the mean of its divisors is an integer number (5455552).

Almost surely, 2^21140233 is an apocalyptic number.

It is an amenable number.

21140233 is a deficient number, since it is larger than the sum of its proper divisors (681975).

21140233 is an equidigital number, since it uses as much as digits as its factorization.

21140233 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 681974.

The product of its (nonzero) digits is 144, while the sum is 16.

The square root of 21140233 is about 4597.8509110235. The cubic root of 21140233 is about 276.5051703419.

Adding to 21140233 its reverse (33204112), we get a palindrome (54344345).

The spelling of 21140233 in words is "twenty-one million, one hundred forty thousand, two hundred thirty-three".