21210111012021 has 16 divisors (see below), whose sum is σ = 28971168914688. Its totient is φ = 13794593587200.

The previous prime is 21210111011951. The next prime is 21210111012043. The reversal of 21210111012021 is 12021011101212.

It is a happy number.

It is not a de Polignac number, because 21210111012021 - 2³¹ = 21207963528373 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21210111012071) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 907981 + ... + 6576066.

It is an arithmetic number, because the mean of its divisors is an integer number (1810698057168).

Almost surely, 2^{21210111012021} is an apocalyptic number.

It is an amenable number.

21210111012021 is a deficient number, since it is larger than the sum of its proper divisors (7761057902667).

21210111012021 is a wasteful number, since it uses less digits than its factorization.

21210111012021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7507132.

The product of its (nonzero) digits is 16, while the sum is 15.

Adding to 21210111012021 its reverse (12021011101212), we get a palindrome (33231122113233).

The spelling of 21210111012021 in words is "twenty-one trillion, two hundred ten billion, one hundred eleven million, twelve thousand, twenty-one".