157709 has 4 divisors (see below), whose sum is σ = 167004. Its totient is φ = 148416.

The previous prime is 157679. The next prime is 157721. The reversal of 157709 is 907751.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 907751 = 13 ⋅69827.

It can be written as a sum of positive squares in 2 ways, for example, as 126025 + 31684 = 355^2 + 178^2 .

It is a cyclic number.

It is not a de Polignac number, because 157709 - 2¹⁶ = 92173 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 11.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (157739) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4622 + ... + 4655.

It is an arithmetic number, because the mean of its divisors is an integer number (41751).

2¹⁵⁷⁷⁰⁹ is an apocalyptic number.

It is an amenable number.

157709 is a deficient number, since it is larger than the sum of its proper divisors (9295).

157709 is an equidigital number, since it uses as much as digits as its factorization.

157709 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9294.

The product of its (nonzero) digits is 2205, while the sum is 29.

The square root of 157709 is about 397.1259246133. The cubic root of 157709 is about 54.0279918888.

The spelling of 157709 in words is "one hundred fifty-seven thousand, seven hundred nine".