561690 has 36 divisors (see below), whose sum is σ = 1479114. Its totient is φ = 147888.

The previous prime is 561667. The next prime is 561703. The reversal of 561690 is 96165.

It can be written as a sum of positive squares in only one way, i.e., 505521 + 56169 = 711^2 + 237^2 .

It is a super-2 number, since 2×561690² = 630991312200, which contains 22 as substring.

It is an Ulam number.

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 7071 + ... + 7149.

2⁵⁶¹⁶⁹⁰ is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 561690, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (739557).

561690 is an abundant number, since it is smaller than the sum of its proper divisors (917424).

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

561690 is a wasteful number, since it uses less digits than its factorization.

561690 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 171 (or 89 counting only the distinct ones).

The product of its (nonzero) digits is 1620, while the sum is 27.

The square root of 561690 is about 749.4598054599. The cubic root of 561690 is about 82.5085390610.

The spelling of 561690 in words is "five hundred sixty-one thousand, six hundred ninety".