212102021 has 6 divisors (see below), whose sum is σ = 221725350. Its totient is φ = 202879688.

The previous prime is 212102003. The next prime is 212102039. The reversal of 212102021 is 120201212.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (212102003) and next prime (212102039).

It can be written as a sum of positive squares in only one way, i.e., 134908225 + 77193796 = 11615^2 + 8786^2 .

It is not a de Polignac number, because 212102021 - 2¹⁴ = 212085637 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 212101993 and 212102011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (212102221) 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 in 5 ways as a sum of consecutive naturals, for example, 199946 + ... + 201003.

It is an arithmetic number, because the mean of its divisors is an integer number (36954225).

Almost surely, 2^212102021 is an apocalyptic number.

It is an amenable number.

212102021 is a deficient number, since it is larger than the sum of its proper divisors (9623329).

212102021 is an equidigital number, since it uses as much as digits as its factorization.

212102021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 400995 (or 400972 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 11.

The square root of 212102021 is about 14563.7227726979. The cubic root of 212102021 is about 596.3688288438.

Adding to 212102021 its reverse (120201212), we get a palindrome (332303233).

The spelling of 212102021 in words is "two hundred twelve million, one hundred two thousand, twenty-one".