2181629 has 2 divisors, whose sum is σ = 2181630. Its totient is φ = 2181628.

The previous prime is 2181611. The next prime is 2181649. The reversal of 2181629 is 9261812.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2181529 + 100 = 1477^2 + 10^2 .

It is a cyclic number.

It is not a de Polignac number, because 2181629 - 2⁸ = 2181373 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2181649) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1090814 + 1090815.

It is an arithmetic number, because the mean of its divisors is an integer number (1090815).

2^2181629 is an apocalyptic number.

It is an amenable number.

2181629 is a deficient number, since it is larger than the sum of its proper divisors (1).

2181629 is an equidigital number, since it uses as much as digits as its factorization.

2181629 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1728, while the sum is 29.

The square root of 2181629 is about 1477.0338520156. The cubic root of 2181629 is about 129.6961146549.

The spelling of 2181629 in words is "two million, one hundred eighty-one thousand, six hundred twenty-nine".