1278618444649 has 32 divisors (see below), whose sum is σ = 1651078768640. Its totient is φ = 962970508800.

The previous prime is 1278618444619. The next prime is 1278618444659. The reversal of 1278618444649 is 9464448168721.

It is a de Polignac number, because none of the positive numbers 2^k-1278618444649 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1278618444619) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3543084 + ... + 3887245.

It is an arithmetic number, because the mean of its divisors is an integer number (51596211520).

Almost surely, 2^{1278618444649} is an apocalyptic number.

It is an amenable number.

1278618444649 is a deficient number, since it is larger than the sum of its proper divisors (372460323991).

1278618444649 is a wasteful number, since it uses less digits than its factorization.

1278618444649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7430441.

The product of its digits is 74317824, while the sum is 64.

The spelling of 1278618444649 in words is "one trillion, two hundred seventy-eight billion, six hundred eighteen million, four hundred forty-four thousand, six hundred forty-nine".