21305153 has 8 divisors (see below), whose sum is σ = 22949376. Its totient is φ = 19720800.

The previous prime is 21305149. The next prime is 21305159. The reversal of 21305153 is 35150312.

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 21305153 - 2² = 21305149 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21305159) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14228 + ... + 15653.

It is an arithmetic number, because the mean of its divisors is an integer number (2868672).

Almost surely, 2^21305153 is an apocalyptic number.

21305153 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

It is an amenable number.

21305153 is a deficient number, since it is larger than the sum of its proper divisors (1644223).

21305153 is a wasteful number, since it uses less digits than its factorization.

21305153 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29935.

The product of its (nonzero) digits is 450, while the sum is 20.

The square root of 21305153 is about 4615.7505348535. The cubic root of 21305153 is about 277.2223362303. Note that the first 3 decimals are identical.

Adding to 21305153 its reverse (35150312), we get a palindrome (56455465).

The spelling of 21305153 in words is "twenty-one million, three hundred five thousand, one hundred fifty-three".