2172861 has 6 divisors (see below), whose sum is σ = 3138590. Its totient is φ = 1448568.

The previous prime is 2172853. The next prime is 2172869. The reversal of 2172861 is 1682712.

It is an interprime number because it is at equal distance from previous prime (2172853) and next prime (2172869).

It can be written as a sum of positive squares in only one way, i.e., 1610361 + 562500 = 1269^2 + 750^2 .

It is not a de Polignac number, because 2172861 - 2³ = 2172853 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2172869) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 120706 + ... + 120723.

2^2172861 is an apocalyptic number.

It is an amenable number.

2172861 is a deficient number, since it is larger than the sum of its proper divisors (965729).

2172861 is a wasteful number, since it uses less digits than its factorization.

2172861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 241435 (or 241432 counting only the distinct ones).

The product of its digits is 1344, while the sum is 27.

The square root of 2172861 is about 1474.0627530740. The cubic root of 2172861 is about 129.5221311490.

The spelling of 2172861 in words is "two million, one hundred seventy-two thousand, eight hundred sixty-one".