212812821 has 24 divisors (see below), whose sum is σ = 332271576. Its totient is φ = 130475520.

The previous prime is 212812793. The next prime is 212812829. The reversal of 212812821 is 128218212.

It can be written as a sum of positive squares in 4 ways, for example, as 2852721 + 209960100 = 1689^2 + 14490^2 .

It is not a de Polignac number, because 212812821 - 2¹⁹ = 212288533 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (212812829) 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 23 ways as a sum of consecutive naturals, for example, 29641 + ... + 36113.

It is an arithmetic number, because the mean of its divisors is an integer number (13844649).

Almost surely, 2^212812821 is an apocalyptic number.

It is an amenable number.

212812821 is a deficient number, since it is larger than the sum of its proper divisors (119458755).

212812821 is a wasteful number, since it uses less digits than its factorization.

212812821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6773 (or 6770 counting only the distinct ones).

The product of its digits is 1024, while the sum is 27.

The square root of 212812821 is about 14588.1054630134. The cubic root of 212812821 is about 597.0342732611.

The spelling of 212812821 in words is "two hundred twelve million, eight hundred twelve thousand, eight hundred twenty-one".