211716200021 has 4 divisors (see below), whose sum is σ = 214396152000. Its totient is φ = 209036248044.

The previous prime is 211716199991. The next prime is 211716200147. The reversal of 211716200021 is 120002617112.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 211716200021 - 2⁶ = 211716199957 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 211716200021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (211716200221) 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, 1339975871 + ... + 1339976028.

It is an arithmetic number, because the mean of its divisors is an integer number (53599038000).

Almost surely, 2^211716200021 is an apocalyptic number.

It is an amenable number.

211716200021 is a deficient number, since it is larger than the sum of its proper divisors (2679951979).

211716200021 is an equidigital number, since it uses as much as digits as its factorization.

211716200021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2679951978.

The product of its (nonzero) digits is 336, while the sum is 23.

Adding to 211716200021 its reverse (120002617112), we get a palindrome (331718817133).

The spelling of 211716200021 in words is "two hundred eleven billion, seven hundred sixteen million, two hundred thousand, twenty-one".