2171509 has 2 divisors, whose sum is σ = 2171510. Its totient is φ = 2171508.

The previous prime is 2171503. The next prime is 2171527. The reversal of 2171509 is 9051712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2160900 + 10609 = 1470^2 + 103^2 .

It is a cyclic number.

It is not a de Polignac number, because 2171509 - 2²¹ = 74357 is a prime.

It is equal to p₁₆₀₇₂₉ and since 2171509 and 160729 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2171503) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1085754 + 1085755.

It is an arithmetic number, because the mean of its divisors is an integer number (1085755).

2^2171509 is an apocalyptic number.

It is an amenable number.

2171509 is a deficient number, since it is larger than the sum of its proper divisors (1).

2171509 is an equidigital number, since it uses as much as digits as its factorization.

2171509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 630, while the sum is 25.

The square root of 2171509 is about 1473.6040852278. The cubic root of 2171509 is about 129.4952617736.

The spelling of 2171509 in words is "two million, one hundred seventy-one thousand, five hundred nine".