212121210101 has 8 divisors (see below), whose sum is σ = 214354723800. Its totient is φ = 209890310400.

The previous prime is 212121210053. The next prime is 212121210109. The reversal of 212121210101 is 101012121212.

212121210101 is an esthetic number in base 10, because in such base its adjacent digits differ by 1.

It can be written as a sum of positive squares in 4 ways, for example, as 182029369201 + 30091840900 = 426649^2 + 173470^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-212121210101 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (212121210109) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 490136 + ... + 815153.

It is an arithmetic number, because the mean of its divisors is an integer number (26794340475).

Almost surely, 2^212121210101 is an apocalyptic number.

It is an amenable number.

212121210101 is a deficient number, since it is larger than the sum of its proper divisors (2233513699).

212121210101 is a wasteful number, since it uses less digits than its factorization.

212121210101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1306999.

The product of its (nonzero) digits is 16, while the sum is 14.

Adding to 212121210101 its reverse (101012121212), we get a palindrome (313133331313).

It can be divided in two parts, 2121212 and 10101, that multiplied together give a palindrome (21426362412).

The spelling of 212121210101 in words is "two hundred twelve billion, one hundred twenty-one million, two hundred ten thousand, one hundred one".