561256560 has 80 divisors (see below), whose sum is σ = 1933224480. Its totient is φ = 149667840.

The previous prime is 561256537. The next prime is 561256573. The reversal of 561256560 is 65652165.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (80).

It is a super-2 number, since 2×561256560² = 630017852286067200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 127761 + ... + 132080.

It is an arithmetic number, because the mean of its divisors is an integer number (24165306).

Almost surely, 2^561256560 is an apocalyptic number.

It is an amenable number.

561256560 is an abundant number, since it is smaller than the sum of its proper divisors (1371967920).

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

561256560 is a wasteful number, since it uses less digits than its factorization.

561256560 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 259863 (or 259851 counting only the distinct ones).

The product of its (nonzero) digits is 54000, while the sum is 36.

The square root of 561256560 is about 23690.8539314226. The cubic root of 561256560 is about 824.8731044498.

The spelling of 561256560 in words is "five hundred sixty-one million, two hundred fifty-six thousand, five hundred sixty".