3687991 has 8 divisors (see below), whose sum is σ = 3803184. Its totient is φ = 3574080.

The previous prime is 3687989. The next prime is 3688001. The reversal of 3687991 is 1997863.

3687991 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 3687991 - 2¹ = 3687989 is a prime.

It is a Duffinian number.

3687991 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3687911) 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 7 ways as a sum of consecutive naturals, for example, 11860 + ... + 12166.

It is an arithmetic number, because the mean of its divisors is an integer number (475398).

Almost surely, 2^3687991 is an apocalyptic number.

3687991 is a deficient number, since it is larger than the sum of its proper divisors (115193).

3687991 is a wasteful number, since it uses less digits than its factorization.

3687991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 641.

The product of its digits is 81648, while the sum is 43.

The square root of 3687991 is about 1920.4142782223. The cubic root of 3687991 is about 154.5005219171.

The spelling of 3687991 in words is "three million, six hundred eighty-seven thousand, nine hundred ninety-one".