5661891 has 12 divisors (see below), whose sum is σ = 8232432. Its totient is φ = 3749616.

The previous prime is 5661839. The next prime is 5661893. The reversal of 5661891 is 1981665.

5661891 is a `hidden beast` number, since 566 + 1 + 8 + 91 = 666.

It is not a de Polignac number, because 5661891 - 2¹⁰ = 5660867 is a prime.

It is not an unprimeable number, because it can be changed into a prime (5661893) 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 11 ways as a sum of consecutive naturals, for example, 591 + ... + 3416.

It is an arithmetic number, because the mean of its divisors is an integer number (686036).

Almost surely, 2^5661891 is an apocalyptic number.

5661891 is a deficient number, since it is larger than the sum of its proper divisors (2570541).

5661891 is a wasteful number, since it uses less digits than its factorization.

5661891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4170 (or 4167 counting only the distinct ones).

The product of its digits is 12960, while the sum is 36.

The square root of 5661891 is about 2379.4728407780. The cubic root of 5661891 is about 178.2326105072.

The spelling of 5661891 in words is "five million, six hundred sixty-one thousand, eight hundred ninety-one".