161751 has 4 divisors (see below), whose sum is σ = 215672. Its totient is φ = 107832.

The previous prime is 161743. The next prime is 161753. The reversal of 161751 is 157161.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 157161 = 3 ⋅52387.

It is not a de Polignac number, because 161751 - 2³ = 161743 is a prime.

It is a D-number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161753) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26956 + ... + 26961.

It is an arithmetic number, because the mean of its divisors is an integer number (53918).

2¹⁶¹⁷⁵¹ is an apocalyptic number.

161751 is a deficient number, since it is larger than the sum of its proper divisors (53921).

161751 is an equidigital number, since it uses as much as digits as its factorization.

161751 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53920.

The product of its digits is 210, while the sum is 21.

The square root of 161751 is about 402.1827942615. The cubic root of 161751 is about 54.4856736465.

The spelling of 161751 in words is "one hundred sixty-one thousand, seven hundred fifty-one".