2605557780 has 576 divisors, whose sum is σ = 10273536000. Its totient is φ = 540836352.

The previous prime is 2605557769. The next prime is 2605557791. The reversal of 2605557780 is 877555062.

2605557780 is a `hidden beast` number, since 26 + 0 + 5 + 557 + 78 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (2605557769) and next prime (2605557791).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 18744951 + ... + 18745089.

It is an arithmetic number, because the mean of its divisors is an integer number (17836000).

Almost surely, 2^2605557780 is an apocalyptic number.

2605557780 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 2605557780, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (5136768000).

2605557780 is an abundant number, since it is smaller than the sum of its proper divisors (7667978220).

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

2605557780 is a wasteful number, since it uses less digits than its factorization.

2605557780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 218 (or 204 counting only the distinct ones).

The product of its (nonzero) digits is 588000, while the sum is 45.

The square root of 2605557780 is about 51044.6645595796. The cubic root of 2605557780 is about 1376.0479556986.

The spelling of 2605557780 in words is "two billion, six hundred five million, five hundred fifty-seven thousand, seven hundred eighty".