911561 has 4 divisors (see below), whose sum is σ = 1041792. Its totient is φ = 781332.

The previous prime is 911549. The next prime is 911593. The reversal of 911561 is 165119.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 165119 = 163 ⋅1013.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-911561 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (911161) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 65105 + ... + 65118.

It is an arithmetic number, because the mean of its divisors is an integer number (260448).

2⁹¹¹⁵⁶¹ is an apocalyptic number.

It is an amenable number.

911561 is a deficient number, since it is larger than the sum of its proper divisors (130231).

911561 is a wasteful number, since it uses less digits than its factorization.

911561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 130230.

The product of its digits is 270, while the sum is 23.

The square root of 911561 is about 954.7570371566. The cubic root of 911561 is about 96.9605890840.

The spelling of 911561 in words is "nine hundred eleven thousand, five hundred sixty-one".