278248261 has 2 divisors, whose sum is σ = 278248262. Its totient is φ = 278248260.

The previous prime is 278248259. The next prime is 278248291. The reversal of 278248261 is 162842872.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 267944161 + 10304100 = 16369^2 + 3210^2 .

It is a cyclic number.

It is not a de Polignac number, because 278248261 - 2¹ = 278248259 is a prime.

Together with 278248259, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (278248211) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 139124130 + 139124131.

It is an arithmetic number, because the mean of its divisors is an integer number (139124131).

Almost surely, 2^278248261 is an apocalyptic number.

It is an amenable number.

278248261 is a deficient number, since it is larger than the sum of its proper divisors (1).

278248261 is an equidigital number, since it uses as much as digits as its factorization.

278248261 is an evil number, because the sum of its binary digits is even.

The product of its digits is 86016, while the sum is 40.

The square root of 278248261 is about 16680.7751918189. The cubic root of 278248261 is about 652.8461083211.

The spelling of 278248261 in words is "two hundred seventy-eight million, two hundred forty-eight thousand, two hundred sixty-one".