21020033 has 4 divisors (see below), whose sum is σ = 21588180. Its totient is φ = 20451888.

The previous prime is 21020029. The next prime is 21020039. The reversal of 21020033 is 33002012.

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 16056049 + 4963984 = 4007^2 + 2228^2 .

It is a cyclic number.

It is not a de Polignac number, because 21020033 - 2² = 21020029 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21019996 and 21020023.

It is not an unprimeable number, because it can be changed into a prime (21020039) 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, 284018 + ... + 284091.

It is an arithmetic number, because the mean of its divisors is an integer number (5397045).

Almost surely, 2^21020033 is an apocalyptic number.

It is an amenable number.

21020033 is a deficient number, since it is larger than the sum of its proper divisors (568147).

21020033 is an equidigital number, since it uses as much as digits as its factorization.

21020033 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 568146.

The product of its (nonzero) digits is 36, while the sum is 11.

The square root of 21020033 is about 4584.7609534195. The cubic root of 21020033 is about 275.9801191659.

Adding to 21020033 its reverse (33002012), we get a palindrome (54022045).

The spelling of 21020033 in words is "twenty-one million, twenty thousand, thirty-three".