561665405 has 32 divisors (see below), whose sum is σ = 812173824. Its totient is φ = 364548096.

The previous prime is 561665389. The next prime is 561665407. The reversal of 561665405 is 504566165.

It is a cyclic number.

It is not a de Polignac number, because 561665405 - 2⁴ = 561665389 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (561665407) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 74489 + ... + 81681.

It is an arithmetic number, because the mean of its divisors is an integer number (25380432).

Almost surely, 2^561665405 is an apocalyptic number.

It is an amenable number.

561665405 is a deficient number, since it is larger than the sum of its proper divisors (250508419).

561665405 is a wasteful number, since it uses less digits than its factorization.

561665405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7325.

The product of its (nonzero) digits is 108000, while the sum is 38.

The square root of 561665405 is about 23699.4811124632. The cubic root of 561665405 is about 825.0733476263.

The spelling of 561665405 in words is "five hundred sixty-one million, six hundred sixty-five thousand, four hundred five".