561257720 has 64 divisors (see below), whose sum is σ = 1407520800. Its totient is φ = 200171520.

The previous prime is 561257713. The next prime is 561257729. The reversal of 561257720 is 27752165.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (561257729) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8801 + ... + 34640.

Almost surely, 2^561257720 is an apocalyptic number.

It is an amenable number.

561257720 is an abundant number, since it is smaller than the sum of its proper divisors (846263080).

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

561257720 is a wasteful number, since it uses less digits than its factorization.

561257720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43488 (or 43484 counting only the distinct ones).

The product of its (nonzero) digits is 29400, while the sum is 35.

The square root of 561257720 is about 23690.8784134316. The cubic root of 561257720 is about 824.8736727295.

The spelling of 561257720 in words is "five hundred sixty-one million, two hundred fifty-seven thousand, seven hundred twenty".