212240021 has 12 divisors (see below), whose sum is σ = 257627232. Its totient is φ = 174009528.

The previous prime is 212240003. The next prime is 212240069. The reversal of 212240021 is 120042212.

It is not a de Polignac number, because 212240021 - 2¹⁰ = 212238997 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 212239978 and 212240005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (212240071) 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 11 ways as a sum of consecutive naturals, for example, 93035 + ... + 95288.

It is an arithmetic number, because the mean of its divisors is an integer number (21468936).

Almost surely, 2^212240021 is an apocalyptic number.

It is an amenable number.

212240021 is a deficient number, since it is larger than the sum of its proper divisors (45387211).

212240021 is a wasteful number, since it uses less digits than its factorization.

212240021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 188360 (or 188353 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 14.

The square root of 212240021 is about 14568.4598019145. The cubic root of 212240021 is about 596.4981393453.

Adding to 212240021 its reverse (120042212), we get a palindrome (332282233).

The spelling of 212240021 in words is "two hundred twelve million, two hundred forty thousand, twenty-one".