1718643649 has 4 divisors (see below), whose sum is σ = 1726020036. Its totient is φ = 1711267264.

The previous prime is 1718643643. The next prime is 1718643659. The reversal of 1718643649 is 9463468171.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9463468171 = 223 ⋅42437077.

It can be written as a sum of positive squares in 2 ways, for example, as 1036389249 + 682254400 = 32193^2 + 26120^2 .

It is a cyclic number.

It is not a de Polignac number, because 1718643649 - 2²⁹ = 1181772737 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1718643643) 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, 3687844 + ... + 3688309.

It is an arithmetic number, because the mean of its divisors is an integer number (431505009).

Almost surely, 2^1718643649 is an apocalyptic number.

It is an amenable number.

1718643649 is a deficient number, since it is larger than the sum of its proper divisors (7376387).

1718643649 is an equidigital number, since it uses as much as digits as its factorization.

1718643649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7376386.

The product of its digits is 870912, while the sum is 49.

The square root of 1718643649 is about 41456.5272182801. The cubic root of 1718643649 is about 1197.8302572207.

The spelling of 1718643649 in words is "one billion, seven hundred eighteen million, six hundred forty-three thousand, six hundred forty-nine".