278005451821 has 2 divisors, whose sum is σ = 278005451822. Its totient is φ = 278005451820.

The previous prime is 278005451741. The next prime is 278005451917. The reversal of 278005451821 is 128154500872.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 245506376196 + 32499075625 = 495486^2 + 180275^2 .

It is a cyclic number.

It is not a de Polignac number, because 278005451821 - 2⁹ = 278005451309 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (278005451221) 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, 139002725910 + 139002725911.

It is an arithmetic number, because the mean of its divisors is an integer number (139002725911).

Almost surely, 2^278005451821 is an apocalyptic number.

It is an amenable number.

278005451821 is a deficient number, since it is larger than the sum of its proper divisors (1).

278005451821 is an equidigital number, since it uses as much as digits as its factorization.

278005451821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 179200, while the sum is 43.

The spelling of 278005451821 in words is "two hundred seventy-eight billion, five million, four hundred fifty-one thousand, eight hundred twenty-one".