172561 has 2 divisors, whose sum is σ = 172562. Its totient is φ = 172560.

The previous prime is 172553. The next prime is 172573. The reversal of 172561 is 165271.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 148225 + 24336 = 385^2 + 156^2 .

It is a cyclic number.

It is not a de Polignac number, because 172561 - 2³ = 172553 is a prime.

It is a super-3 number, since 3×172561³ = 15415201333783443, which contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (172541) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 86280 + 86281.

It is an arithmetic number, because the mean of its divisors is an integer number (86281).

2¹⁷²⁵⁶¹ is an apocalyptic number.

It is an amenable number.

172561 is a deficient number, since it is larger than the sum of its proper divisors (1).

172561 is an equidigital number, since it uses as much as digits as its factorization.

172561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 420, while the sum is 22.

The square root of 172561 is about 415.4046220253. The cubic root of 172561 is about 55.6733749948.

The spelling of 172561 in words is "one hundred seventy-two thousand, five hundred sixty-one".