561720656 has 40 divisors (see below), whose sum is σ = 1245289344. Its totient is φ = 240451200.

The previous prime is 561720637. The next prime is 561720661. The reversal of 561720656 is 656027165.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 110981 + ... + 115931.

Almost surely, 2^561720656 is an apocalyptic number.

561720656 is a gapful number since it is divisible by the number (56) formed by its first and last digit.

It is an amenable number.

561720656 is an abundant number, since it is smaller than the sum of its proper divisors (683568688).

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

561720656 is a wasteful number, since it uses less digits than its factorization.

561720656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5979 (or 5973 counting only the distinct ones).

The product of its (nonzero) digits is 75600, while the sum is 38.

The square root of 561720656 is about 23700.6467422305. The cubic root of 561720656 is about 825.1004008816.

The spelling of 561720656 in words is "five hundred sixty-one million, seven hundred twenty thousand, six hundred fifty-six".