21153213 has 24 divisors (see below), whose sum is σ = 32502080. Its totient is φ = 13219200.

The previous prime is 21153199. The next prime is 21153227. The reversal of 21153213 is 31235112.

It is an interprime number because it is at equal distance from previous prime (21153199) and next prime (21153227).

It is not a de Polignac number, because 21153213 - 2²¹ = 19056061 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 (21153263) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 17013 + ... + 18213.

Almost surely, 2^21153213 is an apocalyptic number.

It is an amenable number.

21153213 is a deficient number, since it is larger than the sum of its proper divisors (11348867).

21153213 is a wasteful number, since it uses less digits than its factorization.

21153213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1329 (or 1326 counting only the distinct ones).

The product of its digits is 180, while the sum is 18.

The square root of 21153213 is about 4599.2622234441. The cubic root of 21153213 is about 276.5617497059.

Adding to 21153213 its reverse (31235112), we get a palindrome (52388325).

The spelling of 21153213 in words is "twenty-one million, one hundred fifty-three thousand, two hundred thirteen".