1561860 has 36 divisors (see below), whose sum is σ = 4738188. Its totient is φ = 416448.

The previous prime is 1561829. The next prime is 1561883. The reversal of 1561860 is 681651.

It can be written as a sum of positive squares in 2 ways, for example, as 484416 + 1077444 = 696^2 + 1038^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is an Ulam number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4159 + ... + 4518.

2^1561860 is an apocalyptic number.

1561860 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1561860 is an abundant number, since it is smaller than the sum of its proper divisors (3176328).

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

1561860 is a wasteful number, since it uses less digits than its factorization.

1561860 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8692 (or 8687 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 27.

The square root of 1561860 is about 1249.7439737802. The cubic root of 1561860 is about 116.0238753868.

It can be divided in two parts, 156 and 1860, that added together give a triangular number (2016 = T₆₃).

The spelling of 1561860 in words is "one million, five hundred sixty-one thousand, eight hundred sixty".