21020063 has 4 divisors (see below), whose sum is σ = 21046488. Its totient is φ = 20993640.

The previous prime is 21020059. The next prime is 21020081. The reversal of 21020063 is 36002012.

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

It is a cyclic number.

It is not a de Polignac number, because 21020063 - 2² = 21020059 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 (21020053) 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, 11981 + ... + 13622.

It is an arithmetic number, because the mean of its divisors is an integer number (5261622).

Almost surely, 2^21020063 is an apocalyptic number.

21020063 is a deficient number, since it is larger than the sum of its proper divisors (26425).

21020063 is an equidigital number, since it uses as much as digits as its factorization.

21020063 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26424.

The product of its (nonzero) digits is 72, while the sum is 14.

The square root of 21020063 is about 4584.7642251265. The cubic root of 21020063 is about 275.9802504597.

Adding to 21020063 its reverse (36002012), we get a palindrome (57022075).

The spelling of 21020063 in words is "twenty-one million, twenty thousand, sixty-three".