15978535203856 has 15 divisors (see below), whose sum is σ = 30958442936701. Its totient is φ = 7989259607296.

The previous prime is 15978535203821. The next prime is 15978535203899. The reversal of 15978535203856 is 65830253587951.

The square root of 15978535203856 is 3997316.

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

It can be written as a sum of positive squares in only one way, i.e., 10582763709456 + 5395771494400 = 3253116^2 + 2322880^2 .

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 15978535203791 and 15978535203800.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 15489600 + ... + 16488928.

Almost surely, 2^{15978535203856} is an apocalyptic number.

15978535203856 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

15978535203856 is the 3997316-th square number.

It is an amenable number.

15978535203856 is a deficient number, since it is larger than the sum of its proper divisors (14979907732845).

15978535203856 is an frugal number, since it uses more digits than its factorization.

15978535203856 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1998666 (or 999331 counting only the distinct ones).

The product of its (nonzero) digits is 272160000, while the sum is 67.

The spelling of 15978535203856 in words is "fifteen trillion, nine hundred seventy-eight billion, five hundred thirty-five million, two hundred three thousand, eight hundred fifty-six".