3685991 has 8 divisors (see below), whose sum is σ = 3977424. Its totient is φ = 3402880.

The previous prime is 3685973. The next prime is 3685999. The reversal of 3685991 is 1995863.

3685991 = T₆₅₀ + T₆₅₁ + ... + T₆₆₆.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-3685991 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a zygodrome in base 2.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3685999) 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 7 ways as a sum of consecutive naturals, for example, 1145 + ... + 2946.

It is an arithmetic number, because the mean of its divisors is an integer number (497178).

Almost surely, 2^3685991 is an apocalyptic number.

3685991 is a deficient number, since it is larger than the sum of its proper divisors (291433).

3685991 is a wasteful number, since it uses less digits than its factorization.

3685991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4161.

The product of its digits is 58320, while the sum is 41.

The square root of 3685991 is about 1919.8934866289. The cubic root of 3685991 is about 154.4725882880.

The spelling of 3685991 in words is "three million, six hundred eighty-five thousand, nine hundred ninety-one".