561728138 has 16 divisors (see below), whose sum is σ = 868150536. Its totient is φ = 272471040.

The previous prime is 561728137. The next prime is 561728143. The reversal of 561728138 is 831827165.

It can be written as a sum of positive squares in 4 ways, for example, as 152596609 + 409131529 = 12353^2 + 20227^2 .

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 561728095 and 561728104.

It is not an unprimeable number, because it can be changed into a prime (561728137) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 22631 + ... + 40442.

Almost surely, 2^561728138 is an apocalyptic number.

561728138 is a deficient number, since it is larger than the sum of its proper divisors (306422398).

561728138 is a wasteful number, since it uses less digits than its factorization.

561728138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 63209.

The product of its digits is 80640, while the sum is 41.

The square root of 561728138 is about 23700.8045854988. The cubic root of 561728138 is about 825.1040642528.

The spelling of 561728138 in words is "five hundred sixty-one million, seven hundred twenty-eight thousand, one hundred thirty-eight".