20323021 has 2 divisors, whose sum is σ = 20323022. Its totient is φ = 20323020.

The previous prime is 20323019. The next prime is 20323031. The reversal of 20323021 is 12032302.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19900521 + 422500 = 4461^2 + 650^2 .

It is a cyclic number.

It is not a de Polignac number, because 20323021 - 2¹ = 20323019 is a prime.

Together with 20323019, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 20322992 and 20323010.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20323031) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10161510 + 10161511.

It is an arithmetic number, because the mean of its divisors is an integer number (10161511).

Almost surely, 2^20323021 is an apocalyptic number.

It is an amenable number.

20323021 is a deficient number, since it is larger than the sum of its proper divisors (1).

20323021 is an equidigital number, since it uses as much as digits as its factorization.

20323021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 72, while the sum is 13.

The square root of 20323021 is about 4508.1061433822. The cubic root of 20323021 is about 272.8953205093.

Adding to 20323021 its reverse (12032302), we get a palindrome (32355323).

The spelling of 20323021 in words is "twenty million, three hundred twenty-three thousand, twenty-one".