21212121202013 has 16 divisors (see below), whose sum is σ = 24371136095616. Its totient is φ = 18085308272640.

The previous prime is 21212121202003. The next prime is 21212121202031. The reversal of 21212121202013 is 31020212121212.

It is not a de Polignac number, because 21212121202013 - 2¹⁶ = 21212121136477 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21212121202003) 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, 9654053 + ... + 11645813.

It is an arithmetic number, because the mean of its divisors is an integer number (1523196005976).

Almost surely, 2^{21212121202013} is an apocalyptic number.

It is an amenable number.

21212121202013 is a deficient number, since it is larger than the sum of its proper divisors (3159014893603).

21212121202013 is a wasteful number, since it uses less digits than its factorization.

21212121202013 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1999844.

The product of its (nonzero) digits is 192, while the sum is 20.

Adding to 21212121202013 its reverse (31020212121212), we get a palindrome (52232333323225).

The spelling of 21212121202013 in words is "twenty-one trillion, two hundred twelve billion, one hundred twenty-one million, two hundred two thousand, thirteen".