211706805549 has 4 divisors (see below), whose sum is σ = 282275740736. Its totient is φ = 141137870364.

The previous prime is 211706805523. The next prime is 211706805553. The reversal of 211706805549 is 945508607112.

It is a happy number.

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 not a de Polignac number, because 211706805549 - 2²⁰ = 211705756973 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 211706805498 and 211706805507.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (211706805049) 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, 35284467589 + ... + 35284467594.

It is an arithmetic number, because the mean of its divisors is an integer number (70568935184).

Almost surely, 2^211706805549 is an apocalyptic number.

It is an amenable number.

211706805549 is a deficient number, since it is larger than the sum of its proper divisors (70568935187).

211706805549 is an equidigital number, since it uses as much as digits as its factorization.

211706805549 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 70568935186.

The product of its (nonzero) digits is 604800, while the sum is 48.

The spelling of 211706805549 in words is "two hundred eleven billion, seven hundred six million, eight hundred five thousand, five hundred forty-nine".