2561544000 has 560 divisors, whose sum is σ = 9780788160. Its totient is φ = 661478400.

The previous prime is 2561543951. The next prime is 2561544023. The reversal of 2561544000 is 4451652.

2561544000 is a `hidden beast` number, since 2 + 5 + 615 + 4 + 40 + 0 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

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 79 ways as a sum of consecutive naturals, for example, 38231967 + ... + 38232033.

Almost surely, 2^2561544000 is an apocalyptic number.

2561544000 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 2561544000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (4890394080).

2561544000 is an abundant number, since it is smaller than the sum of its proper divisors (7219244160).

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

2561544000 is an equidigital number, since it uses as much as digits as its factorization.

2561544000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 165 (or 136 counting only the distinct ones).

The product of its (nonzero) digits is 4800, while the sum is 27.

The square root of 2561544000 is about 50611.6982524791. The cubic root of 2561544000 is about 1368.2557232006.

Adding to 2561544000 its reverse (4451652), we get a palindrome (2565995652).

It can be divided in two parts, 25 and 61544000, that added together give a square (61544025 = 7845²).

The spelling of 2561544000 in words is "two billion, five hundred sixty-one million, five hundred forty-four thousand".