161951 has 4 divisors (see below), whose sum is σ = 164304. Its totient is φ = 159600.

The previous prime is 161947. The next prime is 161957. The reversal of 161951 is 159161.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 161951 - 2² = 161947 is a prime.

It is a Duffinian number.

It is a plaindrome in base 16.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161957) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1070 + ... + 1211.

It is an arithmetic number, because the mean of its divisors is an integer number (41076).

2¹⁶¹⁹⁵¹ is an apocalyptic number.

161951 is a deficient number, since it is larger than the sum of its proper divisors (2353).

161951 is an equidigital number, since it uses as much as digits as its factorization.

161951 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2352.

The product of its digits is 270, while the sum is 23.

The square root of 161951 is about 402.4313606070. The cubic root of 161951 is about 54.5081210018.

The spelling of 161951 in words is "one hundred sixty-one thousand, nine hundred fifty-one".