21210020020111 has 4 divisors (see below), whose sum is σ = 22841560021672. Its totient is φ = 19578480018552.

The previous prime is 21210020020031. The next prime is 21210020020117. The reversal of 21210020020111 is 11102002001212.

It is a semiprime because it is the product of two primes.

It is a de Polignac number, because none of the positive numbers 2^k-21210020020111 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (13), and also a Moran number because the ratio is a prime number: 1631540001547 = 21210020020111 / (2 + 1 + 2 + 1 + 0 + 0 + 2 + 0 + 0 + 2 + 0 + 1 + 1 + 1).

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21210020020091 and 21210020020100.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21210020020117) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 815770000761 + ... + 815770000786.

It is an arithmetic number, because the mean of its divisors is an integer number (5710390005418).

Almost surely, 2^{21210020020111} is an apocalyptic number.

21210020020111 is a deficient number, since it is larger than the sum of its proper divisors (1631540001561).

21210020020111 is a wasteful number, since it uses less digits than its factorization.

21210020020111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1631540001560.

The product of its (nonzero) digits is 16, while the sum is 13.

Adding to 21210020020111 its reverse (11102002001212), we get a palindrome (32312022021323).

The spelling of 21210020020111 in words is "twenty-one trillion, two hundred ten billion, twenty million, twenty thousand, one hundred eleven".