2168767661 has 4 divisors (see below), whose sum is σ = 2169147324. Its totient is φ = 2168388000.

The previous prime is 2168767637. The next prime is 2168767663. The reversal of 2168767661 is 1667678612.

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 1973047561 + 195720100 = 44419^2 + 13990^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2168767661 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 (2168767663) 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, 181130 + ... + 192731.

It is an arithmetic number, because the mean of its divisors is an integer number (542286831).

Almost surely, 2^2168767661 is an apocalyptic number.

It is an amenable number.

2168767661 is a deficient number, since it is larger than the sum of its proper divisors (379663).

2168767661 is an equidigital number, since it uses as much as digits as its factorization.

2168767661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 379662.

The product of its digits is 1016064, while the sum is 50.

The square root of 2168767661 is about 46570.0296435379. The cubic root of 2168767661 is about 1294.4074670329.

The spelling of 2168767661 in words is "two billion, one hundred sixty-eight million, seven hundred sixty-seven thousand, six hundred sixty-one".