2117491865 has 16 divisors (see below), whose sum is σ = 2710113552. Its totient is φ = 1582700544.

The previous prime is 2117491847. The next prime is 2117491867. The reversal of 2117491865 is 5681947112.

It can be written as a sum of positive squares in 8 ways, for example, as 432307264 + 1685184601 = 20792^2 + 41051^2 .

It is not a de Polignac number, because 2117491865 - 2⁸ = 2117491609 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2117491867) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 79274 + ... + 102563.

It is an arithmetic number, because the mean of its divisors is an integer number (169382097).

Almost surely, 2^2117491865 is an apocalyptic number.

It is an amenable number.

2117491865 is a deficient number, since it is larger than the sum of its proper divisors (592621687).

2117491865 is a wasteful number, since it uses less digits than its factorization.

2117491865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 181996.

The product of its digits is 120960, while the sum is 44.

The square root of 2117491865 is about 46016.2130667007. The cubic root of 2117491865 is about 1284.1248493633.

The spelling of 2117491865 in words is "two billion, one hundred seventeen million, four hundred ninety-one thousand, eight hundred sixty-five".