2561220000 has 720 divisors, whose sum is σ = 10316097792. Its totient is φ = 622080000.

The previous prime is 2561219989. The next prime is 2561220019. The reversal of 2561220000 is 221652.

It is a tau number, because it is divible by the number of its divisors (720).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a nialpdrome in base 15.

It is a zygodrome in base 15.

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 119 ways as a sum of consecutive naturals, for example, 82619985 + ... + 82620015.

Almost surely, 2^2561220000 is an apocalyptic number.

2561220000 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 2561220000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (5158048896).

2561220000 is an abundant number, since it is smaller than the sum of its proper divisors (7754877792).

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

2561220000 is an equidigital number, since it uses as much as digits as its factorization.

2561220000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 93 (or 58 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 2561220000 is about 50608.4973102344. The cubic root of 2561220000 is about 1368.1980322732.

Adding to 2561220000 its reverse (221652), we get a palindrome (2561441652).

The spelling of 2561220000 in words is "two billion, five hundred sixty-one million, two hundred twenty thousand".