2116571011666 has 4 divisors (see below), whose sum is σ = 3174856517502. Its totient is φ = 1058285505832.

The previous prime is 2116571011663. The next prime is 2116571011679. The reversal of 2116571011666 is 6661101756112.

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

It can be written as a sum of positive squares in only one way, i.e., 1243615280625 + 872955731041 = 1115175^2 + 934321^2 .

It is not an unprimeable number, because it can be changed into a prime (2116571011661) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 529142752915 + ... + 529142752918.

Almost surely, 2^{2116571011666} is an apocalyptic number.

2116571011666 is a deficient number, since it is larger than the sum of its proper divisors (1058285505836).

2116571011666 is a wasteful number, since it uses less digits than its factorization.

2116571011666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1058285505835.

The product of its (nonzero) digits is 90720, while the sum is 43.

Adding to 2116571011666 its reverse (6661101756112), we get a palindrome (8777672767778).

The spelling of 2116571011666 in words is "two trillion, one hundred sixteen billion, five hundred seventy-one million, eleven thousand, six hundred sixty-six".