4090991 has 2 divisors, whose sum is σ = 4090992. Its totient is φ = 4090990.

The previous prime is 4090973. The next prime is 4090997. The reversal of 4090991 is 1990904.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-4090991 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (4090997) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2045495 + 2045496.

It is an arithmetic number, because the mean of its divisors is an integer number (2045496).

Almost surely, 2^4090991 is an apocalyptic number.

4090991 is a deficient number, since it is larger than the sum of its proper divisors (1).

4090991 is an equidigital number, since it uses as much as digits as its factorization.

4090991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2916, while the sum is 32.

The square root of 4090991 is about 2022.6198357576. The cubic root of 4090991 is about 159.9347520413.

The spelling of 4090991 in words is "four million, ninety thousand, nine hundred ninety-one".