278808161 has 2 divisors, whose sum is σ = 278808162. Its totient is φ = 278808160.

The previous prime is 278808151. The next prime is 278808169. The reversal of 278808161 is 161808872.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 202350625 + 76457536 = 14225^2 + 8744^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-278808161 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (278808169) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 139404080 + 139404081.

It is an arithmetic number, because the mean of its divisors is an integer number (139404081).

Almost surely, 2^278808161 is an apocalyptic number.

It is an amenable number.

278808161 is a deficient number, since it is larger than the sum of its proper divisors (1).

278808161 is an equidigital number, since it uses as much as digits as its factorization.

278808161 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 43008, while the sum is 41.

The square root of 278808161 is about 16697.5495507574. The cubic root of 278808161 is about 653.2837075025.

The spelling of 278808161 in words is "two hundred seventy-eight million, eight hundred eight thousand, one hundred sixty-one".