2172581 has 2 divisors, whose sum is σ = 2172582. Its totient is φ = 2172580.

The previous prime is 2172571. The next prime is 2172587. The reversal of 2172581 is 1852712.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2076481 + 96100 = 1441^2 + 310^2 .

It is a cyclic number.

It is not a de Polignac number, because 2172581 - 2¹⁰ = 2171557 is a prime.

It is a super-2 number, since 2×2172581² = 9440216403122, which contains 22 as substring.

It is an Ulam number.

It is a self number, because there is not a number n which added to its sum of digits gives 2172581.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2172587) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1086290 + 1086291.

It is an arithmetic number, because the mean of its divisors is an integer number (1086291).

2^2172581 is an apocalyptic number.

It is an amenable number.

2172581 is a deficient number, since it is larger than the sum of its proper divisors (1).

2172581 is an equidigital number, since it uses as much as digits as its factorization.

2172581 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1120, while the sum is 26.

The square root of 2172581 is about 1473.9677744103. The cubic root of 2172581 is about 129.5165674008.

The spelling of 2172581 in words is "two million, one hundred seventy-two thousand, five hundred eighty-one".