561891165 has 32 divisors (see below), whose sum is σ = 981835776. Its totient is φ = 272132160.

The previous prime is 561891163. The next prime is 561891167. The reversal of 561891165 is 561198165.

It is an interprime number because it is at equal distance from previous prime (561891163) and next prime (561891167).

It is not a de Polignac number, because 561891165 - 2¹ = 561891163 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (561891163) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 253492 + ... + 255698.

It is an arithmetic number, because the mean of its divisors is an integer number (30682368).

Almost surely, 2^561891165 is an apocalyptic number.

561891165 is a gapful number since it is divisible by the number (55) formed by its first and last digit.

It is an amenable number.

561891165 is a deficient number, since it is larger than the sum of its proper divisors (419944611).

561891165 is a wasteful number, since it uses less digits than its factorization.

561891165 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3769.

The product of its digits is 64800, while the sum is 42.

The square root of 561891165 is about 23704.2436074219. The cubic root of 561891165 is about 825.1838782056.

The spelling of 561891165 in words is "five hundred sixty-one million, eight hundred ninety-one thousand, one hundred sixty-five".