2172005 has 32 divisors (see below), whose sum is σ = 3172608. Its totient is φ = 1408000.

The previous prime is 2171999. The next prime is 2172007. The reversal of 2172005 is 5002712.

2172005 = T₁₃₄ + T₁₃₅ + ... + T₂₄₈.

It is not a de Polignac number, because 2172005 - 2⁴ = 2171989 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (17).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2172007) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 21455 + ... + 21555.

It is an arithmetic number, because the mean of its divisors is an integer number (99144).

2^2172005 is an apocalyptic number.

It is an amenable number.

2172005 is a deficient number, since it is larger than the sum of its proper divisors (1000603).

2172005 is a wasteful number, since it uses less digits than its factorization.

2172005 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 157.

The product of its (nonzero) digits is 140, while the sum is 17.

The square root of 2172005 is about 1473.7723704833. The cubic root of 2172005 is about 129.5051204725.

2172005 divided by its sum of digits (17) gives a triangular number (127765 = T₅₀₅).

Adding to 2172005 its reverse (5002712), we get a palindrome (7174717).

It can be divided in two parts, 217 and 2005, that added together give a palindrome (2222).

The spelling of 2172005 in words is "two million, one hundred seventy-two thousand, five".