561851640 has 240 divisors, whose sum is σ = 2197384200. Its totient is φ = 128386944.

The previous prime is 561851629. The next prime is 561851669. The reversal of 561851640 is 46158165.

561851640 is a `hidden beast` number, since 5 + 6 + 1 + 8 + 5 + 1 + 640 = 666.

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

It is a junction number, because it is equal to n+sod(n) for n = 561851595 and 561851604.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 156991 + ... + 160529.

Almost surely, 2^561851640 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 561851640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1098692100).

561851640 is an abundant number, since it is smaller than the sum of its proper divisors (1635532560).

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

561851640 is a wasteful number, since it uses less digits than its factorization.

561851640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3576 (or 3556 counting only the distinct ones).

The product of its (nonzero) digits is 28800, while the sum is 36.

The square root of 561851640 is about 23703.4098812808. The cubic root of 561851640 is about 825.1645291694.

The spelling of 561851640 in words is "five hundred sixty-one million, eight hundred fifty-one thousand, six hundred forty".