2091997 has 2 divisors, whose sum is σ = 2091998. Its totient is φ = 2091996.

The previous prime is 2091983. The next prime is 2092019. The reversal of 2091997 is 7991902.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1610361 + 481636 = 1269^2 + 694^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2091997 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2091917) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1045998 + 1045999.

It is an arithmetic number, because the mean of its divisors is an integer number (1045999).

2^2091997 is an apocalyptic number.

It is an amenable number.

2091997 is a deficient number, since it is larger than the sum of its proper divisors (1).

2091997 is an equidigital number, since it uses as much as digits as its factorization.

2091997 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 10206, while the sum is 37.

The square root of 2091997 is about 1446.3737414652. The cubic root of 2091997 is about 127.8950352050.

The spelling of 2091997 in words is "two million, ninety-one thousand, nine hundred ninety-seven".