202000021 has 2 divisors, whose sum is σ = 202000022.
Its totient is φ = 202000020.
The previous prime is 202000003. The next prime is 202000063. The reversal of 202000021 is 120000202.
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., 175271121 + 26728900 = 13239^2 + 5170^2
It is a cyclic number.
It is not a de Polignac number, because 202000021 - 211 = 201997973 is a prime.
It is a junction number, because it is equal to n+sod(n) for n = 201999968 and 202000013.
It is a congruent number.
It is not a weakly prime, because it can be changed into another prime (202000081) by changing a digit.
It is a pernicious number, because its binary representation contains a prime number (11) of ones.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 101000010 + 101000011.
It is an arithmetic number, because the mean of its divisors is an integer number (101000011).
Almost surely, 2202000021 is an apocalyptic number.
It is an amenable number.
202000021 is a deficient number, since it is larger than the sum of its proper divisors (1).
202000021 is an equidigital number, since it uses as much as digits as its factorization.
202000021 is an odious number, because the sum of its binary digits is odd.
The product of its (nonzero) digits is 8, while the sum is 7.
The square root of 202000021 is about 14212.6711423293.
The cubic root of 202000021 is about 586.7464511771.
Adding to 202000021 its reverse (120000202), we get a palindrome (322000223).
The spelling of 202000021 in words is "two hundred two million, twenty-one", and thus it is an aban number.