5681991 has 12 divisors (see below), whose sum is σ = 8813112. Its totient is φ = 3246768.

The previous prime is 5681983. The next prime is 5682011. The reversal of 5681991 is 1991865.

It is not a de Polignac number, because 5681991 - 2³ = 5681983 is a prime.

It is an Ulam number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (5681911) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 19180 + ... + 19473.

It is an arithmetic number, because the mean of its divisors is an integer number (734426).

Almost surely, 2^5681991 is an apocalyptic number.

5681991 is a deficient number, since it is larger than the sum of its proper divisors (3131121).

5681991 is a wasteful number, since it uses less digits than its factorization.

5681991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38670 (or 38663 counting only the distinct ones).

The product of its digits is 19440, while the sum is 39.

The square root of 5681991 is about 2383.6927234860. The cubic root of 5681991 is about 178.4432730161.

The spelling of 5681991 in words is "five million, six hundred eighty-one thousand, nine hundred ninety-one".