211166661665 has 16 divisors (see below), whose sum is σ = 258808787712. Its totient is φ = 165327947904.

The previous prime is 211166661649. The next prime is 211166661677. The reversal of 211166661665 is 566166661112.

It is a cyclic number.

It is not a de Polignac number, because 211166661665 - 2⁴ = 211166661649 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (47).

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6577382 + ... + 6609408.

It is an arithmetic number, because the mean of its divisors is an integer number (16175549232).

Almost surely, 2^211166661665 is an apocalyptic number.

It is an amenable number.

211166661665 is a deficient number, since it is larger than the sum of its proper divisors (47642126047).

211166661665 is a wasteful number, since it uses less digits than its factorization.

211166661665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60136.

The product of its digits is 466560, while the sum is 47.

The spelling of 211166661665 in words is "two hundred eleven billion, one hundred sixty-six million, six hundred sixty-one thousand, six hundred sixty-five".