255561220 has 48 divisors (see below), whose sum is σ = 553856688. Its totient is φ = 98979840.

The previous prime is 255561217. The next prime is 255561223. The reversal of 255561220 is 22165552.

255561220 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (255561217) and next prime (255561223).

It can be written as a sum of positive squares in 8 ways, for example, as 52099524 + 203461696 = 7218^2 + 14264^2 .

It is not an unprimeable number, because it can be changed into a prime (255561223) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 177624 + ... + 179056.

It is an arithmetic number, because the mean of its divisors is an integer number (11538681).

Almost surely, 2^255561220 is an apocalyptic number.

255561220 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 255561220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (276928344).

255561220 is an abundant number, since it is smaller than the sum of its proper divisors (298295468).

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

255561220 is a wasteful number, since it uses less digits than its factorization.

255561220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1720 (or 1718 counting only the distinct ones).

The product of its (nonzero) digits is 6000, while the sum is 28.

The square root of 255561220 is about 15986.2822444745. The cubic root of 255561220 is about 634.5974425819.

The spelling of 255561220 in words is "two hundred fifty-five million, five hundred sixty-one thousand, two hundred twenty".