1245138728 has 32 divisors (see below), whose sum is σ = 2351966760. Its totient is φ = 617963520.

The previous prime is 1245138721. The next prime is 1245138731. The reversal of 1245138728 is 8278315421.

It can be written as a sum of positive squares in 4 ways, for example, as 1190112004 + 55026724 = 34498^2 + 7418^2 .

It is not an unprimeable number, because it can be changed into a prime (1245138721) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1322738 + ... + 1323678.

Almost surely, 2^1245138728 is an apocalyptic number.

It is an amenable number.

1245138728 is a deficient number, since it is larger than the sum of its proper divisors (1106828032).

1245138728 is a wasteful number, since it uses less digits than its factorization.

1245138728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1997 (or 1993 counting only the distinct ones).

The product of its digits is 107520, while the sum is 41.

The square root of 1245138728 is about 35286.5233198172. The cubic root of 1245138728 is about 1075.8190917646.

The spelling of 1245138728 in words is "one billion, two hundred forty-five million, one hundred thirty-eight thousand, seven hundred twenty-eight".