21050533 has 4 divisors (see below), whose sum is σ = 24057760. Its totient is φ = 18043308.

The previous prime is 21050527. The next prime is 21050567. The reversal of 21050533 is 33505012.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21050533 - 2¹⁷ = 20919461 is a prime.

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 21050533.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21050503) 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, 1503603 + ... + 1503616.

It is an arithmetic number, because the mean of its divisors is an integer number (6014440).

Almost surely, 2^21050533 is an apocalyptic number.

It is an amenable number.

21050533 is a deficient number, since it is larger than the sum of its proper divisors (3007227).

21050533 is an equidigital number, since it uses as much as digits as its factorization.

21050533 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3007226.

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

The square root of 21050533 is about 4588.0859843730. The cubic root of 21050533 is about 276.1135367444.

Adding to 21050533 its reverse (33505012), we get a palindrome (54555545).

The spelling of 21050533 in words is "twenty-one million, fifty thousand, five hundred thirty-three".