278385641 has 2 divisors, whose sum is σ = 278385642. Its totient is φ = 278385640.

The previous prime is 278385631. The next prime is 278385647. The reversal of 278385641 is 146583872.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 259210000 + 19175641 = 16100^2 + 4379^2 .

It is a cyclic number.

It is not a de Polignac number, because 278385641 - 2⁶ = 278385577 is a prime.

It is a super-2 number, since 2×278385641² = 154997130229961762, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 278385592 and 278385601.

It is not a weakly prime, because it can be changed into another prime (278385647) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 139192820 + 139192821.

It is an arithmetic number, because the mean of its divisors is an integer number (139192821).

Almost surely, 2^278385641 is an apocalyptic number.

It is an amenable number.

278385641 is a deficient number, since it is larger than the sum of its proper divisors (1).

278385641 is an equidigital number, since it uses as much as digits as its factorization.

278385641 is an evil number, because the sum of its binary digits is even.

The product of its digits is 322560, while the sum is 44.

The square root of 278385641 is about 16684.8925977964. The cubic root of 278385641 is about 652.9535342597.

The spelling of 278385641 in words is "two hundred seventy-eight million, three hundred eighty-five thousand, six hundred forty-one".