211550100081 has 4 divisors (see below), whose sum is σ = 282066800112. Its totient is φ = 141033400052.

The previous prime is 211550100079. The next prime is 211550100089. The reversal of 211550100081 is 180001055112.

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 211550100081 - 2¹ = 211550100079 is a prime.

It is a super-2 number, since 2×211550100081² (a number of 23 digits) contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (211550100089) 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, 35258350011 + ... + 35258350016.

It is an arithmetic number, because the mean of its divisors is an integer number (70516700028).

Almost surely, 2^211550100081 is an apocalyptic number.

It is an amenable number.

211550100081 is a deficient number, since it is larger than the sum of its proper divisors (70516700031).

211550100081 is an equidigital number, since it uses as much as digits as its factorization.

211550100081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 70516700030.

The product of its (nonzero) digits is 400, while the sum is 24.

Adding to 211550100081 its reverse (180001055112), we get a palindrome (391551155193).

The spelling of 211550100081 in words is "two hundred eleven billion, five hundred fifty million, one hundred thousand, eighty-one".