21212121210101 has 8 divisors (see below), whose sum is σ = 21495619159680. Its totient is φ = 20928998012832.

The previous prime is 21212121210097. The next prime is 21212121210131. The reversal of 21212121210101 is 10101212121212.

21212121210101 is an esthetic number in base 10, because in such base its adjacent digits differ by 1.

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

It is a cyclic number.

It is not a de Polignac number, because 21212121210101 - 2² = 21212121210097 is a prime.

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

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21212121210101.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21212121210131) 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, 93574115 + ... + 93800528.

It is an arithmetic number, because the mean of its divisors is an integer number (2686952394960).

Almost surely, 2^{21212121210101} is an apocalyptic number.

It is an amenable number.

21212121210101 is a deficient number, since it is larger than the sum of its proper divisors (283497949579).

21212121210101 is a wasteful number, since it uses less digits than its factorization.

21212121210101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 187376155.

The product of its (nonzero) digits is 32, while the sum is 17.

Adding to 21212121210101 its reverse (10101212121212), we get a palindrome (31313333331313).

It can be divided in two parts, 212121212 and 10101, that multiplied together give a palindrome (2142636362412).

The spelling of 21212121210101 in words is "twenty-one trillion, two hundred twelve billion, one hundred twenty-one million, two hundred ten thousand, one hundred one".