561000000 has 392 divisors, whose sum is σ = 2143097568. Its totient is φ = 128000000.

The previous prime is 560999977. The next prime is 561000047. The reversal of 561000000 is 165.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a self number, because there is not a number n which added to its sum of digits gives 561000000.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 55 ways as a sum of consecutive naturals, for example, 32999992 + ... + 33000008.

Almost surely, 2^561000000 is an apocalyptic number.

561000000 is a gapful number since it is divisible by the number (50) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 561000000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1071548784).

561000000 is an abundant number, since it is smaller than the sum of its proper divisors (1582097568).

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

561000000 is an equidigital number, since it uses as much as digits as its factorization.

561000000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 73 (or 38 counting only the distinct ones).

The product of its (nonzero) digits is 30, while the sum is 12.

The square root of 561000000 is about 23685.4385646540. The cubic root of 561000000 is about 824.7473974123.

Adding to 561000000 its reverse (165), we get a palindrome (561000165).

The spelling of 561000000 in words is "five hundred sixty-one million", and thus it is an aban number.