1296728738 has 6 divisors (see below), whose sum is σ = 1945169499. Its totient is φ = 648338906.

The previous prime is 1296728717. The next prime is 1296728743. The reversal of 1296728738 is 8378276921.

It can be written as a sum of positive squares in only one way, i.e., 648364369 + 648364369 = 25463^2 + 25463^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=25463.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1296728738.

It is an unprimeable number.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 38195 + ... + 63657.

Almost surely, 2^1296728738 is an apocalyptic number.

1296728738 is a deficient number, since it is larger than the sum of its proper divisors (648440761).

1296728738 is an frugal number, since it uses more digits than its factorization.

1296728738 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50928 (or 25465 counting only the distinct ones).

The product of its digits is 2032128, while the sum is 53.

The square root of 1296728738 is about 36010.1199387061. The cubic root of 1296728738 is about 1090.4766700056.

The spelling of 1296728738 in words is "one billion, two hundred ninety-six million, seven hundred twenty-eight thousand, seven hundred thirty-eight".