3605991 has 16 divisors (see below), whose sum is σ = 5187840. Its totient is φ = 2220480.

The previous prime is 3605969. The next prime is 3605999. The reversal of 3605991 is 1995063.

It is not a de Polignac number, because 3605991 - 2¹⁰ = 3604967 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3605999) 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 15 ways as a sum of consecutive naturals, for example, 1566 + ... + 3108.

It is an arithmetic number, because the mean of its divisors is an integer number (324240).

Almost surely, 2^3605991 is an apocalyptic number.

3605991 is a deficient number, since it is larger than the sum of its proper divisors (1581849).

3605991 is a wasteful number, since it uses less digits than its factorization.

3605991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1606.

The product of its (nonzero) digits is 7290, while the sum is 33.

The square root of 3605991 is about 1898.9447069359. The cubic root of 3605991 is about 153.3468571353.

The spelling of 3605991 in words is "three million, six hundred five thousand, nine hundred ninety-one".