2561307840 has 672 divisors, whose sum is σ = 11250046080. Its totient is φ = 520224768.

The previous prime is 2561307797. The next prime is 2561307887. The reversal of 2561307840 is 487031652.

It is a tau number, because it is divible by the number of its divisors (672).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 2561307795 and 2561307804.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 7600152 + ... + 7600488.

It is an arithmetic number, because the mean of its divisors is an integer number (16741140).

Almost surely, 2^2561307840 is an apocalyptic number.

2561307840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 2561307840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (5625023040).

2561307840 is an abundant number, since it is smaller than the sum of its proper divisors (8688738240).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

2561307840 is a wasteful number, since it uses less digits than its factorization.

2561307840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 409 (or 396 counting only the distinct ones).

The product of its (nonzero) digits is 40320, while the sum is 36.

The square root of 2561307840 is about 50609.3651412463. The cubic root of 2561307840 is about 1368.2136734053.

The spelling of 2561307840 in words is "two billion, five hundred sixty-one million, three hundred seven thousand, eight hundred forty".