2561665360 has 40 divisors (see below), whose sum is σ = 5961734496. Its totient is φ = 1023657600.

The previous prime is 2561665357. The next prime is 2561665361. The reversal of 2561665360 is 635661652.

It is a happy number.

2561665360 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (40).

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2561665361) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 68847 + ... + 99313.

Almost surely, 2^2561665360 is an apocalyptic number.

2561665360 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

2561665360 is an abundant number, since it is smaller than the sum of its proper divisors (3400069136).

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

2561665360 is a wasteful number, since it uses less digits than its factorization.

2561665360 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31531 (or 31525 counting only the distinct ones).

The product of its (nonzero) digits is 194400, while the sum is 40.

The square root of 2561665360 is about 50612.8971705829. The cubic root of 2561665360 is about 1368.2773311178.

The spelling of 2561665360 in words is "two billion, five hundred sixty-one million, six hundred sixty-five thousand, three hundred sixty".