561870 has 32 divisors (see below), whose sum is σ = 1499040. Its totient is φ = 149760.

The previous prime is 561839. The next prime is 561907. The reversal of 561870 is 78165.

It is a Smith number, since the sum of its digits (27) coincides with the sum of the digits of its prime factors.

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

It is an alternating number because its digits alternate between odd and even.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

561870 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 15 ways as a sum of consecutive naturals, for example, 771 + ... + 1310.

It is an arithmetic number, because the mean of its divisors is an integer number (46845).

2⁵⁶¹⁸⁷⁰ is an apocalyptic number.

561870 is an abundant number, since it is smaller than the sum of its proper divisors (937170).

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

561870 is a wasteful number, since it uses less digits than its factorization.

561870 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2097 (or 2091 counting only the distinct ones).

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

The square root of 561870 is about 749.5798823341. The cubic root of 561870 is about 82.5173517222.

It can be divided in two parts, 561 and 870, that added together give a triangular number (1431 = T₅₃).

The spelling of 561870 in words is "five hundred sixty-one thousand, eight hundred seventy".