1561728 has 96 divisors (see below), whose sum is σ = 4883760. Its totient is φ = 440832.

The previous prime is 1561727. The next prime is 1561741. The reversal of 1561728 is 8271651.

It is a tau number, because it is divible by the number of its divisors (96).

It is an Ulam number.

It is a junction number, because it is equal to n+sod(n) for n = 1561695 and 1561704.

It is not an unprimeable number, because it can be changed into a prime (1561727) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 18775 + ... + 18857.

2^1561728 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 1561728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2441880).

1561728 is an abundant number, since it is smaller than the sum of its proper divisors (3322032).

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

1561728 is an equidigital number, since it uses as much as digits as its factorization.

1561728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 114 (or 95 counting only the distinct ones).

The product of its digits is 3360, while the sum is 30.

The square root of 1561728 is about 1249.6911618476. The cubic root of 1561728 is about 116.0206067236.

The spelling of 1561728 in words is "one million, five hundred sixty-one thousand, seven hundred twenty-eight".