2172261 has 32 divisors (see below), whose sum is σ = 3646720. Its totient is φ = 1119744.

The previous prime is 2172257. The next prime is 2172283. The reversal of 2172261 is 1622712.

It is not a de Polignac number, because 2172261 - 2² = 2172257 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2172211) 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, 19875 + ... + 19983.

It is an arithmetic number, because the mean of its divisors is an integer number (113960).

2^2172261 is an apocalyptic number.

2172261 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

2172261 is a deficient number, since it is larger than the sum of its proper divisors (1474459).

2172261 is a wasteful number, since it uses less digits than its factorization.

2172261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 205.

The product of its digits is 336, while the sum is 21.

The square root of 2172261 is about 1473.8592198714. The cubic root of 2172261 is about 129.5102082460.

Adding to 2172261 its reverse (1622712), we get a palindrome (3794973).

The spelling of 2172261 in words is "two million, one hundred seventy-two thousand, two hundred sixty-one".