2181551 has 2 divisors, whose sum is σ = 2181552. Its totient is φ = 2181550.

The previous prime is 2181547. The next prime is 2181577. The reversal of 2181551 is 1551812.

2181551 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 2181551 - 2² = 2181547 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2181541) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1090775 + 1090776.

It is an arithmetic number, because the mean of its divisors is an integer number (1090776).

2^2181551 is an apocalyptic number.

2181551 is a deficient number, since it is larger than the sum of its proper divisors (1).

2181551 is an equidigital number, since it uses as much as digits as its factorization.

2181551 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 400, while the sum is 23.

The square root of 2181551 is about 1477.0074475100. The cubic root of 2181551 is about 129.6945689571.

The spelling of 2181551 in words is "two million, one hundred eighty-one thousand, five hundred fifty-one".