211643689 has 4 divisors (see below), whose sum is σ = 213516756. Its totient is φ = 209770624.

The previous prime is 211643669. The next prime is 211643699. The reversal of 211643689 is 986346112.

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 1625625 + 210018064 = 1275^2 + 14492^2 .

It is a cyclic number.

It is not a de Polignac number, because 211643689 - 2⁵ = 211643657 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (211643629) 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, 936364 + ... + 936589.

It is an arithmetic number, because the mean of its divisors is an integer number (53379189).

Almost surely, 2^211643689 is an apocalyptic number.

It is an amenable number.

211643689 is a deficient number, since it is larger than the sum of its proper divisors (1873067).

211643689 is a wasteful number, since it uses less digits than its factorization.

211643689 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1873066.

The product of its digits is 62208, while the sum is 40.

The square root of 211643689 is about 14547.9788630586. The cubic root of 211643689 is about 595.9389538919.

The spelling of 211643689 in words is "two hundred eleven million, six hundred forty-three thousand, six hundred eighty-nine".