561997920 has 192 divisors, whose sum is σ = 1946052864. Its totient is φ = 135198720.

The previous prime is 561997913. The next prime is 561997927. The reversal of 561997920 is 29799165.

It is an interprime number because it is at equal distance from previous prime (561997913) and next prime (561997927).

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a self number, because there is not a number n which added to its sum of digits gives 561997920.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (561997927) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 860314 + ... + 860966.

It is an arithmetic number, because the mean of its divisors is an integer number (10135692).

Almost surely, 2^561997920 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 561997920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (973026432).

561997920 is an abundant number, since it is smaller than the sum of its proper divisors (1384054944).

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

561997920 is a wasteful number, since it uses less digits than its factorization.

561997920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 845 (or 837 counting only the distinct ones).

The product of its (nonzero) digits is 306180, while the sum is 48.

The square root of 561997920 is about 23706.4953124666. The cubic root of 561997920 is about 825.2361344265.

The spelling of 561997920 in words is "five hundred sixty-one million, nine hundred ninety-seven thousand, nine hundred twenty".