2181541 has 2 divisors, whose sum is σ = 2181542. Its totient is φ = 2181540.

The previous prime is 2181539. The next prime is 2181547. The reversal of 2181541 is 1451812.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2117025 + 64516 = 1455^2 + 254^2 .

It is a cyclic number.

It is not a de Polignac number, because 2181541 - 2¹ = 2181539 is a prime.

It is a super-2 number, since 2×2181541² = 9518242269362, which contains 22 as substring.

Together with 2181539, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2181547) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1090770 + 1090771.

It is an arithmetic number, because the mean of its divisors is an integer number (1090771).

2^2181541 is an apocalyptic number.

It is an amenable number.

2181541 is a deficient number, since it is larger than the sum of its proper divisors (1).

2181541 is an equidigital number, since it uses as much as digits as its factorization.

2181541 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 320, while the sum is 22.

The square root of 2181541 is about 1477.0040622828. The cubic root of 2181541 is about 129.6943707881.

The spelling of 2181541 in words is "two million, one hundred eighty-one thousand, five hundred forty-one".