278230781 has 2 divisors, whose sum is σ = 278230782. Its totient is φ = 278230780.

The previous prime is 278230681. The next prime is 278230807. The reversal of 278230781 is 187032872.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 235131556 + 43099225 = 15334^2 + 6565^2 .

It is a cyclic number.

It is not a de Polignac number, because 278230781 - 2¹⁸ = 277968637 is a prime.

It is a super-2 number, since 2×278230781² = 154824734991739922, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (278230681) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 139115390 + 139115391.

It is an arithmetic number, because the mean of its divisors is an integer number (139115391).

Almost surely, 2^278230781 is an apocalyptic number.

It is an amenable number.

278230781 is a deficient number, since it is larger than the sum of its proper divisors (1).

278230781 is an equidigital number, since it uses as much as digits as its factorization.

278230781 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 37632, while the sum is 38.

The square root of 278230781 is about 16680.2512271248. The cubic root of 278230781 is about 652.8324370899.

The spelling of 278230781 in words is "two hundred seventy-eight million, two hundred thirty thousand, seven hundred eighty-one".