20312021 has 2 divisors, whose sum is σ = 20312022. Its totient is φ = 20312020.

The previous prime is 20311981. The next prime is 20312053. The reversal of 20312021 is 12021302.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15689521 + 4622500 = 3961^2 + 2150^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20312021 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 20311993 and 20312011.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20312221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10156010 + 10156011.

It is an arithmetic number, because the mean of its divisors is an integer number (10156011).

Almost surely, 2^20312021 is an apocalyptic number.

It is an amenable number.

20312021 is a deficient number, since it is larger than the sum of its proper divisors (1).

20312021 is an equidigital number, since it uses as much as digits as its factorization.

20312021 is an odious number, because the sum of its binary digits is odd.

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

The square root of 20312021 is about 4506.8859537379. The cubic root of 20312021 is about 272.8460760215.

Adding to 20312021 its reverse (12021302), we get a palindrome (32333323).

The spelling of 20312021 in words is "twenty million, three hundred twelve thousand, twenty-one".