1561680 has 100 divisors (see below), whose sum is σ = 5446452. Its totient is φ = 414720.

The previous prime is 1561673. The next prime is 1561697. The reversal of 1561680 is 861651.

It can be written as a sum of positive squares in 2 ways, for example, as 876096 + 685584 = 936^2 + 828^2 .

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 6360 + ... + 6600.

2^1561680 is an apocalyptic number.

1561680 is a gapful number since it is divisible by the number (10) 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 1561680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2723226).

1561680 is an abundant number, since it is smaller than the sum of its proper divisors (3884772).

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

1561680 is a wasteful number, since it uses less digits than its factorization.

1561680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 266 (or 251 counting only the distinct ones).

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

The square root of 1561680 is about 1249.6719569551. The cubic root of 1561680 is about 116.0194180731.

The spelling of 1561680 in words is "one million, five hundred sixty-one thousand, six hundred eighty".