561811960 has 32 divisors (see below), whose sum is σ = 1267131600. Its totient is φ = 224181760.

The previous prime is 561811919. The next prime is 561811963. The reversal of 561811960 is 69118165.

561811960 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

561811960 is a nontrivial binomial coefficient, being equal to C(33521, 2).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (561811963) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1 + ... + 33520.

Almost surely, 2^561811960 is an apocalyptic number.

561811960 is the 33520-th triangular number.

561811960 is the 11174-th centered nonagonal number.

It is an amenable number.

561811960 is an abundant number, since it is smaller than the sum of its proper divisors (705319640).

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

561811960 is a wasteful number, since it uses less digits than its factorization.

561811960 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33951 (or 33947 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 37.

The square root of 561811960 is about 23702.5728561268. The cubic root of 561811960 is about 825.1451033417.

It can be divided in two parts, 5618 and 11960, that added together give a triangular number (17578 = T₁₈₇).

The spelling of 561811960 in words is "five hundred sixty-one million, eight hundred eleven thousand, nine hundred sixty".