161687 has 4 divisors (see below), whose sum is σ = 171216. Its totient is φ = 152160.

The previous prime is 161683. The next prime is 161717. The reversal of 161687 is 786161.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 786161 = 29 ⋅27109.

It is a cyclic number.

It is not a de Polignac number, because 161687 - 2² = 161683 is a prime.

It is a super-2 number, since 2×161687² = 52285371938, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 161687.

It is not an unprimeable number, because it can be changed into a prime (161683) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4739 + ... + 4772.

It is an arithmetic number, because the mean of its divisors is an integer number (42804).

2¹⁶¹⁶⁸⁷ is an apocalyptic number.

161687 is a gapful number since it is divisible by the number (17) formed by its first and last digit.

161687 is a deficient number, since it is larger than the sum of its proper divisors (9529).

161687 is an equidigital number, since it uses as much as digits as its factorization.

161687 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9528.

The product of its digits is 2016, while the sum is 29.

The square root of 161687 is about 402.1032205790. The cubic root of 161687 is about 54.4784865851.

It can be divided in two parts, 161 and 687, that added together give a palindrome (848).

The spelling of 161687 in words is "one hundred sixty-one thousand, six hundred eighty-seven".