561780 has 36 divisors (see below), whose sum is σ = 1704612. Its totient is φ = 149760.

The previous prime is 561767. The next prime is 561787. The reversal of 561780 is 87165.

It can be written as a sum of positive squares in 2 ways, for example, as 60516 + 501264 = 246^2 + 708^2 .

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (561787) by changing a digit.

561780 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1381 + ... + 1740.

2⁵⁶¹⁷⁸⁰ is an apocalyptic number.

It is an amenable number.

561780 is an abundant number, since it is smaller than the sum of its proper divisors (1142832).

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

561780 is a wasteful number, since it uses less digits than its factorization.

561780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3136 (or 3131 counting only the distinct ones).

The product of its (nonzero) digits is 1680, while the sum is 27.

The square root of 561780 is about 749.5198463016. The cubic root of 561780 is about 82.5129456269.

It can be divided in two parts, 561 and 780, that multiplied together give a triangular number (437580 = T₉₃₅).

The spelling of 561780 in words is "five hundred sixty-one thousand, seven hundred eighty".