2172561 has 4 divisors (see below), whose sum is σ = 2896752. Its totient is φ = 1448372.

The previous prime is 2172559. The next prime is 2172563. The reversal of 2172561 is 1652712.

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.

It is an interprime number because it is at equal distance from previous prime (2172559) and next prime (2172563).

It is a cyclic number.

It is not a de Polignac number, because 2172561 - 2¹ = 2172559 is a prime.

It is a D-number.

It is not an unprimeable number, because it can be changed into a prime (2172563) 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, 362091 + ... + 362096.

It is an arithmetic number, because the mean of its divisors is an integer number (724188).

2^2172561 is an apocalyptic number.

It is an amenable number.

2172561 is a deficient number, since it is larger than the sum of its proper divisors (724191).

2172561 is an equidigital number, since it uses as much as digits as its factorization.

2172561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 724190.

The product of its digits is 840, while the sum is 24.

The square root of 2172561 is about 1473.9609899858. The cubic root of 2172561 is about 129.5161699719.

The spelling of 2172561 in words is "two million, one hundred seventy-two thousand, five hundred sixty-one".