3990691 has 4 divisors (see below), whose sum is σ = 4045432. Its totient is φ = 3935952.

The previous prime is 3990689. The next prime is 3990731. The reversal of 3990691 is 1960993.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 3990691 - 2¹ = 3990689 is a prime.

It is a super-2 number, since 2×3990691² = 31851229314962, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 3990691.

It is not an unprimeable number, because it can be changed into a prime (3990601) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 27261 + ... + 27406.

It is an arithmetic number, because the mean of its divisors is an integer number (1011358).

Almost surely, 2^3990691 is an apocalyptic number.

3990691 is a deficient number, since it is larger than the sum of its proper divisors (54741).

3990691 is an equidigital number, since it uses as much as digits as its factorization.

3990691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54740.

The product of its (nonzero) digits is 13122, while the sum is 37.

The square root of 3990691 is about 1997.6713943990. The cubic root of 3990691 is about 158.6168669086.

The spelling of 3990691 in words is "three million, nine hundred ninety thousand, six hundred ninety-one".