2091709 has 2 divisors, whose sum is σ = 2091710. Its totient is φ = 2091708.

The previous prime is 2091707. The next prime is 2091737. The reversal of 2091709 is 9071902.

It is an a-pointer prime, because the next prime (2091737) can be obtained adding 2091709 to its sum of digits (28).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1863225 + 228484 = 1365^2 + 478^2 .

It is a cyclic number.

It is not a de Polignac number, because 2091709 - 2¹ = 2091707 is a prime.

Together with 2091707, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2091703) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1045854 + 1045855.

It is an arithmetic number, because the mean of its divisors is an integer number (1045855).

2^2091709 is an apocalyptic number.

It is an amenable number.

2091709 is a deficient number, since it is larger than the sum of its proper divisors (1).

2091709 is an equidigital number, since it uses as much as digits as its factorization.

2091709 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1134, while the sum is 28.

The square root of 2091709 is about 1446.2741787089. The cubic root of 2091709 is about 127.8891659390.

The spelling of 2091709 in words is "two million, ninety-one thousand, seven hundred nine".