2561002561100 has 72 divisors (see below), whose sum is σ = 5702526921168. Its totient is φ = 997729331200.

The previous prime is 2561002561093. The next prime is 2561002561111. The reversal of 2561002561100 is 11652001652.

It is a happy number.

2561002561100 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1904627 + ... + 2957973.

It is an arithmetic number, because the mean of its divisors is an integer number (79201762794).

Almost surely, 2^{2561002561100} is an apocalyptic number.

2561002561100 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 2561002561100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2851263460584).

2561002561100 is an abundant number, since it is smaller than the sum of its proper divisors (3141524360068).

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

2561002561100 is a wasteful number, since it uses less digits than its factorization.

2561002561100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1053995 (or 1053988 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 29.

Adding to 2561002561100 its reverse (11652001652), we get a palindrome (2572654562752).

The spelling of 2561002561100 in words is "two trillion, five hundred sixty-one billion, two million, five hundred sixty-one thousand, one hundred".