1278448657 has 2 divisors, whose sum is σ = 1278448658. Its totient is φ = 1278448656.

The previous prime is 1278448631. The next prime is 1278448663. The reversal of 1278448657 is 7568448721.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1001026321 + 277422336 = 31639^2 + 16656^2 .

It is a cyclic number.

It is not a de Polignac number, because 1278448657 - 2⁷ = 1278448529 is a prime.

It is not a weakly prime, because it can be changed into another prime (1278448357) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 639224328 + 639224329.

It is an arithmetic number, because the mean of its divisors is an integer number (639224329).

Almost surely, 2^1278448657 is an apocalyptic number.

It is an amenable number.

1278448657 is a deficient number, since it is larger than the sum of its proper divisors (1).

1278448657 is an equidigital number, since it uses as much as digits as its factorization.

1278448657 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3010560, while the sum is 52.

The square root of 1278448657 is about 35755.4003893118. The cubic root of 1278448657 is about 1085.3282242278.

The spelling of 1278448657 in words is "one billion, two hundred seventy-eight million, four hundred forty-eight thousand, six hundred fifty-seven".