278722421 has 2 divisors, whose sum is σ = 278722422. Its totient is φ = 278722420.

The previous prime is 278722391. The next prime is 278722439. The reversal of 278722421 is 124227872.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 274564900 + 4157521 = 16570^2 + 2039^2 .

It is a cyclic number.

It is not a de Polignac number, because 278722421 - 2¹⁰ = 278721397 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (278722621) 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, 139361210 + 139361211.

It is an arithmetic number, because the mean of its divisors is an integer number (139361211).

Almost surely, 2^278722421 is an apocalyptic number.

It is an amenable number.

278722421 is a deficient number, since it is larger than the sum of its proper divisors (1).

278722421 is an equidigital number, since it uses as much as digits as its factorization.

278722421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 25088, while the sum is 35.

The square root of 278722421 is about 16694.9819107419. The cubic root of 278722421 is about 653.2167339874.

The spelling of 278722421 in words is "two hundred seventy-eight million, seven hundred twenty-two thousand, four hundred twenty-one".