215843782261 has 2 divisors, whose sum is σ = 215843782262. Its totient is φ = 215843782260.

The previous prime is 215843782201. The next prime is 215843782303. The reversal of 215843782261 is 162287348512.

215843782261 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 214730292100 + 1113490161 = 463390^2 + 33369^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-215843782261 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (215843782201) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 107921891130 + 107921891131.

It is an arithmetic number, because the mean of its divisors is an integer number (107921891131).

Almost surely, 2^215843782261 is an apocalyptic number.

It is an amenable number.

215843782261 is a deficient number, since it is larger than the sum of its proper divisors (1).

215843782261 is an equidigital number, since it uses as much as digits as its factorization.

215843782261 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1290240, while the sum is 49.

The spelling of 215843782261 in words is "two hundred fifteen billion, eight hundred forty-three million, seven hundred eighty-two thousand, two hundred sixty-one".