3991669 has 8 divisors (see below), whose sum is σ = 4392000. Its totient is φ = 3627580.

The previous prime is 3991667. The next prime is 3991679. The reversal of 3991669 is 9661993.

It is not a de Polignac number, because 3991669 - 2¹ = 3991667 is a prime.

It is a super-2 number, since 2×3991669² = 31866842811122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3991667) 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, 169 + ... + 2830.

It is an arithmetic number, because the mean of its divisors is an integer number (549000).

Almost surely, 2^3991669 is an apocalyptic number.

It is an amenable number.

3991669 is a deficient number, since it is larger than the sum of its proper divisors (400331).

3991669 is an equidigital number, since it uses as much as digits as its factorization.

3991669 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3032 (or 3010 counting only the distinct ones).

The product of its digits is 78732, while the sum is 43.

The square root of 3991669 is about 1997.9161644073. The cubic root of 3991669 is about 158.6298232801.

The spelling of 3991669 in words is "three million, nine hundred ninety-one thousand, six hundred sixty-nine".