3991087 has 2 divisors, whose sum is σ = 3991088. Its totient is φ = 3991086.

The previous prime is 3991051. The next prime is 3991093. The reversal of 3991087 is 7801993.

It is a strong prime.

It is an emirp because it is prime and its reverse (7801993) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 3991087 - 2¹¹ = 3989039 is a prime.

It is an Ulam number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (3991037) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1995543 + 1995544.

It is an arithmetic number, because the mean of its divisors is an integer number (1995544).

Almost surely, 2^3991087 is an apocalyptic number.

3991087 is a deficient number, since it is larger than the sum of its proper divisors (1).

3991087 is an equidigital number, since it uses as much as digits as its factorization.

3991087 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 13608, while the sum is 37.

The square root of 3991087 is about 1997.7705073406. The cubic root of 3991087 is about 158.6221133018.

The spelling of 3991087 in words is "three million, nine hundred ninety-one thousand, eighty-seven".