278390012009 has 2 divisors, whose sum is σ = 278390012010. Its totient is φ = 278390012008.

The previous prime is 278390011981. The next prime is 278390012027. The reversal of 278390012009 is 900210093872.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 221732683225 + 56657328784 = 470885^2 + 238028^2 .

It is a cyclic number.

It is not a de Polignac number, because 278390012009 - 2¹⁶ = 278389946473 is a prime.

It is not a weakly prime, because it can be changed into another prime (278390012059) 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, 139195006004 + 139195006005.

It is an arithmetic number, because the mean of its divisors is an integer number (139195006005).

Almost surely, 2^278390012009 is an apocalyptic number.

It is an amenable number.

278390012009 is a deficient number, since it is larger than the sum of its proper divisors (1).

278390012009 is an equidigital number, since it uses as much as digits as its factorization.

278390012009 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 54432, while the sum is 41.

The spelling of 278390012009 in words is "two hundred seventy-eight billion, three hundred ninety million, twelve thousand, nine".