2561842397 has 8 divisors (see below), whose sum is σ = 2700186840. Its totient is φ = 2426831680.

The previous prime is 2561842379. The next prime is 2561842441. The reversal of 2561842397 is 7932481652.

It can be written as a sum of positive squares in 4 ways, for example, as 1582527961 + 979314436 = 39781^2 + 31294^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 2561842397 - 2²⁶ = 2494733533 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 (2561842307) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 831854 + ... + 834927.

It is an arithmetic number, because the mean of its divisors is an integer number (337523355).

Almost surely, 2^2561842397 is an apocalyptic number.

It is an amenable number.

2561842397 is a deficient number, since it is larger than the sum of its proper divisors (138344443).

2561842397 is a wasteful number, since it uses less digits than its factorization.

2561842397 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1666863.

The product of its digits is 725760, while the sum is 47.

The square root of 2561842397 is about 50614.6460720610. The cubic root of 2561842397 is about 1368.3088509952.

The spelling of 2561842397 in words is "two billion, five hundred sixty-one million, eight hundred forty-two thousand, three hundred ninety-seven".