211670605661 has 4 divisors (see below), whose sum is σ = 211680963132. Its totient is φ = 211660248192.

The previous prime is 211670605633. The next prime is 211670605673. The reversal of 211670605661 is 166506076112.

211670605661 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It can be written as a sum of positive squares in 2 ways, for example, as 163240240900 + 48430364761 = 404030^2 + 220069^2 .

It is a cyclic number.

It is not a de Polignac number, because 211670605661 - 2¹⁰ = 211670604637 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (211670605061) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5148020 + ... + 5188973.

It is an arithmetic number, because the mean of its divisors is an integer number (52920240783).

Almost surely, 2^211670605661 is an apocalyptic number.

It is an amenable number.

211670605661 is a deficient number, since it is larger than the sum of its proper divisors (10357471).

211670605661 is a wasteful number, since it uses less digits than its factorization.

211670605661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10357470.

The product of its (nonzero) digits is 90720, while the sum is 41.

The spelling of 211670605661 in words is "two hundred eleven billion, six hundred seventy million, six hundred five thousand, six hundred sixty-one".