561307640 has 64 divisors (see below), whose sum is σ = 1334707200. Its totient is φ = 212015232.

The previous prime is 561307639. The next prime is 561307679. The reversal of 561307640 is 46703165.

It is a junction number, because it is equal to n+sod(n) for n = 561307597 and 561307606.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 68819 + ... + 76541.

It is an arithmetic number, because the mean of its divisors is an integer number (20854800).

Almost surely, 2^561307640 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 561307640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (667353600).

561307640 is an abundant number, since it is smaller than the sum of its proper divisors (773399560).

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

561307640 is a wasteful number, since it uses less digits than its factorization.

561307640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7836 (or 7832 counting only the distinct ones).

The product of its (nonzero) digits is 15120, while the sum is 32.

The square root of 561307640 is about 23691.9319600576. The cubic root of 561307640 is about 824.8981276109.

The spelling of 561307640 in words is "five hundred sixty-one million, three hundred seven thousand, six hundred forty".