172661 has 4 divisors (see below), whose sum is σ = 180192. Its totient is φ = 165132.

The previous prime is 172657. The next prime is 172663. The reversal of 172661 is 166271.

172661 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 166271 = 7 ⋅23753.

It is a cyclic number.

It is not a de Polignac number, because 172661 - 2² = 172657 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (23), and also a Moran number because the ratio is a prime number: 7507 = 172661 / (1 + 7 + 2 + 6 + 6 + 1).

It is a Duffinian number.

It is a plaindrome in base 14.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (172663) 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, 3731 + ... + 3776.

It is an arithmetic number, because the mean of its divisors is an integer number (45048).

2¹⁷²⁶⁶¹ is an apocalyptic number.

It is an amenable number.

172661 is a deficient number, since it is larger than the sum of its proper divisors (7531).

172661 is an equidigital number, since it uses as much as digits as its factorization.

172661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7530.

The product of its digits is 504, while the sum is 23.

The square root of 172661 is about 415.5249691655. The cubic root of 172661 is about 55.6841272552.

The spelling of 172661 in words is "one hundred seventy-two thousand, six hundred sixty-one".