21050353 has 4 divisors (see below), whose sum is σ = 21338788. Its totient is φ = 20761920.

The previous prime is 21050339. The next prime is 21050357. The reversal of 21050353 is 35305012.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 16064064 + 4986289 = 4008^2 + 2233^2 .

It is a cyclic number.

It is not a de Polignac number, because 21050353 - 2⁹ = 21049841 is a prime.

It is a super-3 number, since 3×21050353³ (a number of 23 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21050353.

It is not an unprimeable number, because it can be changed into a prime (21050357) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 144108 + ... + 144253.

It is an arithmetic number, because the mean of its divisors is an integer number (5334697).

Almost surely, 2^21050353 is an apocalyptic number.

It is an amenable number.

21050353 is a deficient number, since it is larger than the sum of its proper divisors (288435).

21050353 is an equidigital number, since it uses as much as digits as its factorization.

21050353 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 288434.

The product of its (nonzero) digits is 450, while the sum is 19.

The square root of 21050353 is about 4588.0663683081. The cubic root of 21050353 is about 276.1127497401.

Adding to 21050353 its reverse (35305012), we get a palindrome (56355365).

The spelling of 21050353 in words is "twenty-one million, fifty thousand, three hundred fifty-three".