21353303 has 6 divisors (see below), whose sum is σ = 21655224. Its totient is φ = 21055536.

The previous prime is 21353281. The next prime is 21353347. The reversal of 21353303 is 30335312.

It is not a de Polignac number, because 21353303 - 2⁸ = 21353047 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 (21353383) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 3326 + ... + 7332.

It is an arithmetic number, because the mean of its divisors is an integer number (3609204).

Almost surely, 2^21353303 is an apocalyptic number.

21353303 is a deficient number, since it is larger than the sum of its proper divisors (301921).

21353303 is an frugal number, since it uses more digits than its factorization.

21353303 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4153 (or 4080 counting only the distinct ones).

The product of its (nonzero) digits is 810, while the sum is 20.

The square root of 21353303 is about 4620.9634276848. The cubic root of 21353303 is about 277.4310214615.

Adding to 21353303 its reverse (30335312), we get a palindrome (51688615).

Subtracting 21353303 from its reverse (30335312), we obtain a square (8982009 = 2997²).

The spelling of 21353303 in words is "twenty-one million, three hundred fifty-three thousand, three hundred three".