211041661 has 4 divisors (see below), whose sum is σ = 211225852. Its totient is φ = 210857472.

The previous prime is 211041659. The next prime is 211041713. The reversal of 211041661 is 166140112.

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 59382436 + 151659225 = 7706^2 + 12315^2 .

It is a cyclic number.

It is not a de Polignac number, because 211041661 - 2¹ = 211041659 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 (211041631) 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, 90366 + ... + 92671.

It is an arithmetic number, because the mean of its divisors is an integer number (52806463).

Almost surely, 2^211041661 is an apocalyptic number.

It is an amenable number.

211041661 is a deficient number, since it is larger than the sum of its proper divisors (184191).

211041661 is a wasteful number, since it uses less digits than its factorization.

211041661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 184190.

The product of its (nonzero) digits is 288, while the sum is 22.

The square root of 211041661 is about 14527.2730063147. The cubic root of 211041661 is about 595.3733607533.

Adding to 211041661 its reverse (166140112), we get a palindrome (377181773).

The spelling of 211041661 in words is "two hundred eleven million, forty-one thousand, six hundred sixty-one".