2491357789 has 4 divisors (see below), whose sum is σ = 2498496700. Its totient is φ = 2484218880.

The previous prime is 2491357763. The next prime is 2491357793. The reversal of 2491357789 is 9877531942.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9877531942 = 2 ⋅4938765971.

It can be written as a sum of positive squares in 2 ways, for example, as 1714788100 + 776569689 = 41410^2 + 27867^2 .

It is a cyclic number.

It is not a de Polignac number, because 2491357789 - 2⁹ = 2491357277 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 (2491357489) 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, 3568932 + ... + 3569629.

It is an arithmetic number, because the mean of its divisors is an integer number (624624175).

Almost surely, 2^2491357789 is an apocalyptic number.

It is an amenable number.

2491357789 is a deficient number, since it is larger than the sum of its proper divisors (7138911).

2491357789 is an equidigital number, since it uses as much as digits as its factorization.

2491357789 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7138910.

The product of its digits is 3810240, while the sum is 55.

The square root of 2491357789 is about 49913.5030728159. The cubic root of 2491357789 is about 1355.6430980971.

The spelling of 2491357789 in words is "two billion, four hundred ninety-one million, three hundred fifty-seven thousand, seven hundred eighty-nine".