2108668657 has 4 divisors (see below), whose sum is σ = 2108800116. Its totient is φ = 2108537200.

The previous prime is 2108668651. The next prime is 2108668699. The reversal of 2108668657 is 7568668012.

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 745508416 + 1363160241 = 27304^2 + 36921^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2108668657 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 2108668657.

It is not an unprimeable number, because it can be changed into a prime (2108668651) 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, 37678 + ... + 75079.

It is an arithmetic number, because the mean of its divisors is an integer number (527200029).

Almost surely, 2^2108668657 is an apocalyptic number.

It is an amenable number.

2108668657 is a deficient number, since it is larger than the sum of its proper divisors (131459).

2108668657 is a wasteful number, since it uses less digits than its factorization.

2108668657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 131458.

The product of its (nonzero) digits is 967680, while the sum is 49.

The square root of 2108668657 is about 45920.2423447438. The cubic root of 2108668657 is about 1282.3387938585.

The spelling of 2108668657 in words is "two billion, one hundred eight million, six hundred sixty-eight thousand, six hundred fifty-seven".