21152233 has 4 divisors (see below), whose sum is σ = 22396500. Its totient is φ = 19907968.

The previous prime is 21152207. The next prime is 21152237. The reversal of 21152233 is 33225112.

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

It can be written as a sum of positive squares in 2 ways, for example, as 19607184 + 1545049 = 4428^2 + 1243^2 .

It is a cyclic number.

It is not a de Polignac number, because 21152233 - 2⁹ = 21151721 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21152233.

It is not an unprimeable number, because it can be changed into a prime (21152237) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 622108 + ... + 622141.

It is an arithmetic number, because the mean of its divisors is an integer number (5599125).

Almost surely, 2^21152233 is an apocalyptic number.

It is an amenable number.

21152233 is a deficient number, since it is larger than the sum of its proper divisors (1244267).

21152233 is a wasteful number, since it uses less digits than its factorization.

21152233 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1244266.

The product of its digits is 360, while the sum is 19.

The square root of 21152233 is about 4599.1556833836. The cubic root of 21152233 is about 276.5574787282.

Adding to 21152233 its reverse (33225112), we get a palindrome (54377345).

The spelling of 21152233 in words is "twenty-one million, one hundred fifty-two thousand, two hundred thirty-three".