561333865 has 16 divisors (see below), whose sum is σ = 695735568. Its totient is φ = 434543616.

The previous prime is 561333793. The next prime is 561333869. The reversal of 561333865 is 568333165.

It can be written as a sum of positive squares in 8 ways, for example, as 4892944 + 556440921 = 2212^2 + 23589^2 .

It is a 4-Lehmer number, since φ(561333865) divides (561333865-1)⁴.

It is a cyclic number.

It is not a de Polignac number, because 561333865 - 2²⁹ = 24462953 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (561333869) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4837 + ... + 33853.

It is an arithmetic number, because the mean of its divisors is an integer number (43483473).

Almost surely, 2^561333865 is an apocalyptic number.

561333865 is the 19345-th pentagonal number.

It is an amenable number.

561333865 is a deficient number, since it is larger than the sum of its proper divisors (134401703).

561333865 is a wasteful number, since it uses less digits than its factorization.

561333865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29148.

The product of its digits is 194400, while the sum is 40.

The square root of 561333865 is about 23692.4854120457. The cubic root of 561333865 is about 824.9109741707.

The spelling of 561333865 in words is "five hundred sixty-one million, three hundred thirty-three thousand, eight hundred sixty-five".