561537639 has 12 divisors (see below), whose sum is σ = 873503176. Its totient is φ = 345561552.

The previous prime is 561537637. The next prime is 561537677. The reversal of 561537639 is 936735165.

561537639 is a `hidden beast` number, since 5 + 6 + 1 + 5 + 3 + 7 + 639 = 666.

It is not a de Polignac number, because 561537639 - 2¹ = 561537637 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 561537594 and 561537603.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (561537637) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2399617 + ... + 2399850.

Almost surely, 2^561537639 is an apocalyptic number.

561537639 is a deficient number, since it is larger than the sum of its proper divisors (311965537).

561537639 is a wasteful number, since it uses less digits than its factorization.

561537639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4799486 (or 4799483 counting only the distinct ones).

The product of its digits is 510300, while the sum is 45.

The square root of 561537639 is about 23696.7854149039. The cubic root of 561537639 is about 825.0107811263.

The spelling of 561537639 in words is "five hundred sixty-one million, five hundred thirty-seven thousand, six hundred thirty-nine".