21063021 has 8 divisors (see below), whose sum is σ = 32096064. Its totient is φ = 12036000.

The previous prime is 21063013. The next prime is 21063041. The reversal of 21063021 is 12036012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21063021 - 2³ = 21063013 is a prime.

It is a Smith number, since the sum of its digits (15) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21063041) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 501480 + ... + 501521.

It is an arithmetic number, because the mean of its divisors is an integer number (4012008).

Almost surely, 2^21063021 is an apocalyptic number.

21063021 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21063021 is a deficient number, since it is larger than the sum of its proper divisors (11033043).

21063021 is a wasteful number, since it uses less digits than its factorization.

21063021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1003011.

The product of its (nonzero) digits is 72, while the sum is 15.

The square root of 21063021 is about 4589.4466986773. The cubic root of 21063021 is about 276.1681264029.

Adding to 21063021 its reverse (12036012), we get a palindrome (33099033).

The spelling of 21063021 in words is "twenty-one million, sixty-three thousand, twenty-one".