2181779213 has 2 divisors, whose sum is σ = 2181779214. Its totient is φ = 2181779212.

The previous prime is 2181779191. The next prime is 2181779221. The reversal of 2181779213 is 3129771812.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1969406884 + 212372329 = 44378^2 + 14573^2 .

It is a cyclic number.

It is not a de Polignac number, because 2181779213 - 2⁸ = 2181778957 is a prime.

It is a Sophie Germain 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 (2181779263) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1090889606 + 1090889607.

It is an arithmetic number, because the mean of its divisors is an integer number (1090889607).

Almost surely, 2^2181779213 is an apocalyptic number.

It is an amenable number.

2181779213 is a deficient number, since it is larger than the sum of its proper divisors (1).

2181779213 is an equidigital number, since it uses as much as digits as its factorization.

2181779213 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 42336, while the sum is 41.

The square root of 2181779213 is about 46709.5195115514. The cubic root of 2181779213 is about 1296.9909126786.

The spelling of 2181779213 in words is "two billion, one hundred eighty-one million, seven hundred seventy-nine thousand, two hundred thirteen".