561665423 has 6 divisors (see below), whose sum is σ = 617367912. Its totient is φ = 510604820.

The previous prime is 561665413. The next prime is 561665453. The reversal of 561665423 is 324566165.

It is a happy number.

It is not a de Polignac number, because 561665423 - 2⁴ = 561665407 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (561665413) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2320811 + ... + 2321052.

It is an arithmetic number, because the mean of its divisors is an integer number (102894652).

Almost surely, 2^561665423 is an apocalyptic number.

561665423 is a deficient number, since it is larger than the sum of its proper divisors (55702489).

561665423 is a wasteful number, since it uses less digits than its factorization.

561665423 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4641885 (or 4641874 counting only the distinct ones).

The product of its digits is 129600, while the sum is 38.

The square root of 561665423 is about 23699.4814922183. The cubic root of 561665423 is about 825.0733564401.

The spelling of 561665423 in words is "five hundred sixty-one million, six hundred sixty-five thousand, four hundred twenty-three".