2491399061 has 4 divisors (see below), whose sum is σ = 2491509324. Its totient is φ = 2491288800.

The previous prime is 2491399049. The next prime is 2491399067. The reversal of 2491399061 is 1609931942.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 1609931942 = 2 ⋅804965971.

It can be written as a sum of positive squares in 2 ways, for example, as 972816100 + 1518582961 = 31190^2 + 38969^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2491399061 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2491399067) 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, 7550 + ... + 70991.

It is an arithmetic number, because the mean of its divisors is an integer number (622877331).

Almost surely, 2^2491399061 is an apocalyptic number.

It is an amenable number.

2491399061 is a deficient number, since it is larger than the sum of its proper divisors (110263).

2491399061 is an equidigital number, since it uses as much as digits as its factorization.

2491399061 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 110262.

The product of its (nonzero) digits is 104976, while the sum is 44.

The square root of 2491399061 is about 49913.9165063212. The cubic root of 2491399061 is about 1355.6505839472.

The spelling of 2491399061 in words is "two billion, four hundred ninety-one million, three hundred ninety-nine thousand, sixty-one".