212021 has 4 divisors (see below), whose sum is σ = 223200. Its totient is φ = 200844.

The previous prime is 211997. The next prime is 212029. The reversal of 212021 is 120212.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-212021 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (212029) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5561 + ... + 5598.

It is an arithmetic number, because the mean of its divisors is an integer number (55800).

2²¹²⁰²¹ is an apocalyptic number.

It is an amenable number.

212021 is a deficient number, since it is larger than the sum of its proper divisors (11179).

212021 is a wasteful number, since it uses less digits than its factorization.

212021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11178.

The product of its (nonzero) digits is 8, while the sum is 8.

The square root of 212021 is about 460.4573813069. The cubic root of 212021 is about 59.6292883390.

Adding to 212021 its reverse (120212), we get a palindrome (332233).

Subtracting from 212021 its reverse (120212), we obtain a square (91809 = 303²).

It can be divided in two parts, 2 and 12021, that multiplied together give a palindrome (24042).

The spelling of 212021 in words is "two hundred twelve thousand, twenty-one", and thus it is an iban number.