3991306 has 12 divisors (see below), whose sum is σ = 6581106. Its totient is φ = 1814120.

The previous prime is 3991297. The next prime is 3991313. The reversal of 3991306 is 6031993.

It can be written as a sum of positive squares in only one way, i.e., 3964081 + 27225 = 1991^2 + 165^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 8005 + ... + 8488.

Almost surely, 2^3991306 is an apocalyptic number.

3991306 is a deficient number, since it is larger than the sum of its proper divisors (2589800).

3991306 is a wasteful number, since it uses less digits than its factorization.

3991306 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16517 (or 16506 counting only the distinct ones).

The product of its (nonzero) digits is 4374, while the sum is 31.

The square root of 3991306 is about 1997.8253176892. The cubic root of 3991306 is about 158.6250145671.

The spelling of 3991306 in words is "three million, nine hundred ninety-one thousand, three hundred six".