21153205 has 8 divisors (see below), whose sum is σ = 25974432. Its totient is φ = 16528848.

The previous prime is 21153199. The next prime is 21153227. The reversal of 21153205 is 50235112.

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

It is a cyclic number.

It is not a de Polignac number, because 21153205 - 2¹⁹ = 20628917 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 48979 + ... + 49408.

It is an arithmetic number, because the mean of its divisors is an integer number (3246804).

Almost surely, 2^21153205 is an apocalyptic number.

It is an amenable number.

21153205 is a deficient number, since it is larger than the sum of its proper divisors (4821227).

21153205 is an equidigital number, since it uses as much as digits as its factorization.

21153205 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 98435.

The product of its (nonzero) digits is 300, while the sum is 19.

The square root of 21153205 is about 4599.2613537393. The cubic root of 21153205 is about 276.5617148413.

Adding to 21153205 its reverse (50235112), we get a palindrome (71388317).

The spelling of 21153205 in words is "twenty-one million, one hundred fifty-three thousand, two hundred five".