1278331969 has 2 divisors, whose sum is σ = 1278331970. Its totient is φ = 1278331968.

The previous prime is 1278331939. The next prime is 1278331979. The reversal of 1278331969 is 9691338721.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 814360369 + 463971600 = 28537^2 + 21540^2 .

It is a cyclic number.

It is not a de Polignac number, because 1278331969 - 2¹⁵ = 1278299201 is a prime.

It is a super-2 number, since 2×1278331969² = 3268265245934833922, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1278331939) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 639165984 + 639165985.

It is an arithmetic number, because the mean of its divisors is an integer number (639165985).

Almost surely, 2^1278331969 is an apocalyptic number.

It is an amenable number.

1278331969 is a deficient number, since it is larger than the sum of its proper divisors (1).

1278331969 is an equidigital number, since it uses as much as digits as its factorization.

1278331969 is an evil number, because the sum of its binary digits is even.

The product of its digits is 489888, while the sum is 49.

The square root of 1278331969 is about 35753.7685985687. The cubic root of 1278331969 is about 1085.2952027914.

The spelling of 1278331969 in words is "one billion, two hundred seventy-eight million, three hundred thirty-one thousand, nine hundred sixty-nine".