216010021 has 2 divisors, whose sum is σ = 216010022. Its totient is φ = 216010020.

The previous prime is 216010019. The next prime is 216010057. The reversal of 216010021 is 120010612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 214769025 + 1240996 = 14655^2 + 1114^2 .

It is a cyclic number.

It is not a de Polignac number, because 216010021 - 2¹ = 216010019 is a prime.

Together with 216010019, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 216009983 and 216010010.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (216010001) 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, 108005010 + 108005011.

It is an arithmetic number, because the mean of its divisors is an integer number (108005011).

Almost surely, 2^216010021 is an apocalyptic number.

It is an amenable number.

216010021 is a deficient number, since it is larger than the sum of its proper divisors (1).

216010021 is an equidigital number, since it uses as much as digits as its factorization.

216010021 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 13.

The square root of 216010021 is about 14697.2793740883. The cubic root of 216010021 is about 600.0092785602.

Adding to 216010021 its reverse (120010612), we get a palindrome (336020633).

The spelling of 216010021 in words is "two hundred sixteen million, ten thousand, twenty-one".