21012121213 has 2 divisors, whose sum is σ = 21012121214. Its totient is φ = 21012121212.

The previous prime is 21012121189. The next prime is 21012121237. The reversal of 21012121213 is 31212121012.

It is a balanced prime because it is at equal distance from previous prime (21012121189) and next prime (21012121237).

It can be written as a sum of positive squares in only one way, i.e., 20960669284 + 51451929 = 144778^2 + 7173^2 .

It is a cyclic number.

It is not a de Polignac number, because 21012121213 - 2⁵ = 21012121181 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21012128213) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10506060606 + 10506060607.

It is an arithmetic number, because the mean of its divisors is an integer number (10506060607).

Almost surely, 2^21012121213 is an apocalyptic number.

It is an amenable number.

21012121213 is a deficient number, since it is larger than the sum of its proper divisors (1).

21012121213 is an equidigital number, since it uses as much as digits as its factorization.

21012121213 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 48, while the sum is 16.

Adding to 21012121213 its reverse (31212121012), we get a palindrome (52224242225).

The spelling of 21012121213 in words is "twenty-one billion, twelve million, one hundred twenty-one thousand, two hundred thirteen".