21202420211 has 16 divisors (see below), whose sum is σ = 25662273024. Its totient is φ = 17123889024.

The previous prime is 21202420157. The next prime is 21202420243. The reversal of 21202420211 is 11202420212.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21202420211 is a prime.

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 21202420211.

It is not an unprimeable number, because it can be changed into a prime (21202420711) 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, 971990 + ... + 993563.

It is an arithmetic number, because the mean of its divisors is an integer number (1603892064).

Almost surely, 2^21202420211 is an apocalyptic number.

21202420211 is a deficient number, since it is larger than the sum of its proper divisors (4459852813).

21202420211 is a wasteful number, since it uses less digits than its factorization.

21202420211 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1965650.

The product of its (nonzero) digits is 128, while the sum is 17.

Adding to 21202420211 its reverse (11202420212), we get a palindrome (32404840423).

Subtracting from 21202420211 its reverse (11202420212), we obtain a palindrome (9999999999).

The spelling of 21202420211 in words is "twenty-one billion, two hundred two million, four hundred twenty thousand, two hundred eleven".