168921 has 9 divisors (see below), whose sum is σ = 245791. Its totient is φ = 111792.

The previous prime is 168913. The next prime is 168937. The reversal of 168921 is 129861.

168921 = T₄₁₀ + T₄₁₁.

The square root of 168921 is 411.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 99225 + 69696 = 315^2 + 264^2 .

It is a tau number, because it is divible by the number of its divisors (9).

It is not a de Polignac number, because 168921 - 2³ = 168913 is a prime.

It is a Duffinian number.

It is a plaindrome in base 14.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 168921.

It is not an unprimeable number, because it can be changed into a prime (168901) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 1165 + ... + 1301.

2¹⁶⁸⁹²¹ is an apocalyptic number.

168921 is the 411-st square number.

168921 is the 206-th centered octagonal number.

It is an amenable number.

168921 is a deficient number, since it is larger than the sum of its proper divisors (76870).

168921 is an equidigital number, since it uses as much as digits as its factorization.

168921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 280 (or 140 counting only the distinct ones).

The product of its digits is 864, while the sum is 27.

The cubic root of 168921 is about 55.2791319379.

Subtracting from 168921 its reverse (129861), we obtain a triangular number (39060 = T₂₇₉).

It can be divided in two parts, 168 and 921, that added together give a square (1089 = 33²).

The spelling of 168921 in words is "one hundred sixty-eight thousand, nine hundred twenty-one".