212121101 has 4 divisors (see below), whose sum is σ = 212155104. Its totient is φ = 212087100.

The previous prime is 212121067. The next prime is 212121113. The reversal of 212121101 is 101121212.

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-212121101 is a prime.

It is a super-3 number, since 3×212121101³ (a number of 26 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (212121181) 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 3 ways as a sum of consecutive naturals, for example, 4655 + ... + 21116.

It is an arithmetic number, because the mean of its divisors is an integer number (53038776).

Almost surely, 2^212121101 is an apocalyptic number.

It is an amenable number.

212121101 is a deficient number, since it is larger than the sum of its proper divisors (34003).

212121101 is an equidigital number, since it uses as much as digits as its factorization.

212121101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34002.

The product of its (nonzero) digits is 8, while the sum is 11.

The square root of 212121101 is about 14564.3778102602. The cubic root of 212121101 is about 596.3867107669.

Adding to 212121101 its reverse (101121212), we get a palindrome (313242313).

The spelling of 212121101 in words is "two hundred twelve million, one hundred twenty-one thousand, one hundred one".