1387978515625 has 99 divisors (see below), whose sum is σ = 1945715292183. Its totient is φ = 989625000000.

The previous prime is 1387978515619. The next prime is 1387978515631. The reversal of 1387978515625 is 5265158797831.

The square root of 1387978515625 is 1178125.

It is a perfect power (a square), and thus also a powerful number.

It is an interprime number because it is at equal distance from previous prime (1387978515619) and next prime (1387978515631).

It can be written as a sum of positive squares in 49 ways, for example, as 1274250395929 + 113728119696 = 1128827^2 + 337236^2 .

It is a de Polignac number, because none of the positive numbers 2^k-1387978515625 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 98 ways as a sum of consecutive naturals, for example, 47861328111 + ... + 47861328139.

Almost surely, 2^{1387978515625} is an apocalyptic number.

1387978515625 is the 1178125-th square number.

1387978515625 is the 589063-rd centered octagonal number.

It is an amenable number.

1387978515625 is a deficient number, since it is larger than the sum of its proper divisors (557736776558).

1387978515625 is an frugal number, since it uses more digits than its factorization.

1387978515625 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 134 (or 47 counting only the distinct ones).

The product of its digits is 127008000, while the sum is 67.

The spelling of 1387978515625 in words is "one trillion, three hundred eighty-seven billion, nine hundred seventy-eight million, five hundred fifteen thousand, six hundred twenty-five".