561778728 has 96 divisors (see below), whose sum is σ = 1638617760. Its totient is φ = 160030080.

The previous prime is 561778687. The next prime is 561778751. The reversal of 561778728 is 827877165.

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, 635775 + ... + 636657.

It is an arithmetic number, because the mean of its divisors is an integer number (17068935).

Almost surely, 2^561778728 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 561778728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (819308880).

561778728 is an abundant number, since it is smaller than the sum of its proper divisors (1076839032).

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

561778728 is a wasteful number, since it uses less digits than its factorization.

561778728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1447 (or 1436 counting only the distinct ones).

The product of its digits is 1317120, while the sum is 51.

The square root of 561778728 is about 23701.8718248159. The cubic root of 561778728 is about 825.1288335073.

The spelling of 561778728 in words is "five hundred sixty-one million, seven hundred seventy-eight thousand, seven hundred twenty-eight".