21302021 has 8 divisors (see below), whose sum is σ = 24148320. Its totient is φ = 18628272.

The previous prime is 21301997. The next prime is 21302027. The reversal of 21302021 is 12020312.

It is a happy number.

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

It is not a de Polignac number, because 21302021 - 2⁶ = 21301957 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21301993 and 21302011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21302027) 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, 42875 + ... + 43368.

It is an arithmetic number, because the mean of its divisors is an integer number (3018540).

Almost surely, 2^21302021 is an apocalyptic number.

It is an amenable number.

21302021 is a deficient number, since it is larger than the sum of its proper divisors (2846299).

21302021 is a wasteful number, since it uses less digits than its factorization.

21302021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 86275.

The product of its (nonzero) digits is 24, while the sum is 11.

The square root of 21302021 is about 4615.4112492821. The cubic root of 21302021 is about 277.2087510520.

Adding to 21302021 its reverse (12020312), we get a palindrome (33322333).

The spelling of 21302021 in words is "twenty-one million, three hundred two thousand, twenty-one".