278721609137 has 2 divisors, whose sum is σ = 278721609138. Its totient is φ = 278721609136.

The previous prime is 278721609079. The next prime is 278721609149. The reversal of 278721609137 is 731906127872.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 191052913216 + 87668695921 = 437096^2 + 296089^2 .

It is a cyclic number.

It is not a de Polignac number, because 278721609137 - 2⁸ = 278721608881 is a prime.

It is not a weakly prime, because it can be changed into another prime (278721609167) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 139360804568 + 139360804569.

It is an arithmetic number, because the mean of its divisors is an integer number (139360804569).

Almost surely, 2^278721609137 is an apocalyptic number.

It is an amenable number.

278721609137 is a deficient number, since it is larger than the sum of its proper divisors (1).

278721609137 is an equidigital number, since it uses as much as digits as its factorization.

278721609137 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1778112, while the sum is 53.

The spelling of 278721609137 in words is "two hundred seventy-eight billion, seven hundred twenty-one million, six hundred nine thousand, one hundred thirty-seven".