1278703561 has 12 divisors (see below), whose sum is σ = 1352868048. Its totient is φ = 1208330024.

The previous prime is 1278703549. The next prime is 1278703571. The reversal of 1278703561 is 1653078721.

It is not a de Polignac number, because 1278703561 - 2⁵ = 1278703529 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1278703511) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 29346 + ... + 58468.

It is an arithmetic number, because the mean of its divisors is an integer number (112739004).

Almost surely, 2^1278703561 is an apocalyptic number.

It is an amenable number.

1278703561 is a deficient number, since it is larger than the sum of its proper divisors (74164487).

1278703561 is an equidigital number, since it uses as much as digits as its factorization.

1278703561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29252 (or 29229 counting only the distinct ones).

The product of its (nonzero) digits is 70560, while the sum is 40.

The square root of 1278703561 is about 35758.9647640980. The cubic root of 1278703561 is about 1085.4003523025.

The spelling of 1278703561 in words is "one billion, two hundred seventy-eight million, seven hundred three thousand, five hundred sixty-one".