21153211 has 8 divisors (see below), whose sum is σ = 21677040. Its totient is φ = 20635008.

The previous prime is 21153199. The next prime is 21153227. The reversal of 21153211 is 11235112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21153211 is a prime.

It is a super-2 number, since 2×21153211² = 894916671221042, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21153281) 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 7 ways as a sum of consecutive naturals, for example, 6775 + ... + 9391.

It is an arithmetic number, because the mean of its divisors is an integer number (2709630).

Almost surely, 2^21153211 is an apocalyptic number.

21153211 is a deficient number, since it is larger than the sum of its proper divisors (523829).

21153211 is a wasteful number, since it uses less digits than its factorization.

21153211 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2813.

The product of its digits is 60, while the sum is 16.

The square root of 21153211 is about 4599.2620060179. The cubic root of 21153211 is about 276.5617409898.

Adding to 21153211 its reverse (11235112), we get a palindrome (32388323).

The spelling of 21153211 in words is "twenty-one million, one hundred fifty-three thousand, two hundred eleven".