2491155865 has 12 divisors (see below), whose sum is σ = 3285855972. Its totient is φ = 1811749280.

The previous prime is 2491155853. The next prime is 2491155889. The reversal of 2491155865 is 5685511942.

It can be written as a sum of positive squares in 2 ways, for example, as 956788624 + 1534367241 = 30932^2 + 39171^2 .

It is not a de Polignac number, because 2491155865 - 2⁵ = 2491155833 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2058202 + ... + 2059411.

It is an arithmetic number, because the mean of its divisors is an integer number (273821331).

Almost surely, 2^2491155865 is an apocalyptic number.

It is an amenable number.

2491155865 is a deficient number, since it is larger than the sum of its proper divisors (794700107).

2491155865 is a wasteful number, since it uses less digits than its factorization.

2491155865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4117640 (or 4117629 counting only the distinct ones).

The product of its digits is 432000, while the sum is 46.

The square root of 2491155865 is about 49911.4802926140. The cubic root of 2491155865 is about 1355.6064722494.

The spelling of 2491155865 in words is "two billion, four hundred ninety-one million, one hundred fifty-five thousand, eight hundred sixty-five".