212121022009 has 16 divisors (see below), whose sum is σ = 241892315280. Its totient is φ = 184273367040.

The previous prime is 212121021977. The next prime is 212121022021. The reversal of 212121022009 is 900220121212.

It can be written as a sum of positive squares in 8 ways, for example, as 2125210000 + 209995812009 = 46100^2 + 458253^2 .

It is a cyclic number.

It is not a de Polignac number, because 212121022009 - 2⁵ = 212121021977 is a prime.

It is a super-3 number, since 3×212121022009³ (a number of 35 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (212121022409) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4655679 + ... + 4701019.

It is an arithmetic number, because the mean of its divisors is an integer number (15118269705).

Almost surely, 2^212121022009 is an apocalyptic number.

It is an amenable number.

212121022009 is a deficient number, since it is larger than the sum of its proper divisors (29771293271).

212121022009 is a wasteful number, since it uses less digits than its factorization.

212121022009 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66540.

The product of its (nonzero) digits is 288, while the sum is 22.

The spelling of 212121022009 in words is "two hundred twelve billion, one hundred twenty-one million, twenty-two thousand, nine".