166551 has 24 divisors (see below), whose sum is σ = 284544. Its totient is φ = 85680.

The previous prime is 166541. The next prime is 166561. The reversal of 166551 is 155661.

166551 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (166541) and next prime (166561).

It is not a de Polignac number, because 166551 - 2⁶ = 166487 is a prime.

It is an Ulam number.

166551 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166541) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1566 + ... + 1668.

It is an arithmetic number, because the mean of its divisors is an integer number (11856).

2¹⁶⁶⁵⁵¹ is an apocalyptic number.

166551 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

166551 is a deficient number, since it is larger than the sum of its proper divisors (117993).

166551 is a wasteful number, since it uses less digits than its factorization.

166551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 131 (or 124 counting only the distinct ones).

The product of its digits is 900, while the sum is 24.

The square root of 166551 is about 408.1066037202. The cubic root of 166551 is about 55.0193871048.

It can be divided in two parts, 166 and 551, that added together give a palindrome (717).

The spelling of 166551 in words is "one hundred sixty-six thousand, five hundred fifty-one".