15978603243 has 4 divisors (see below), whose sum is σ = 21304804328. Its totient is φ = 10652402160.

The previous prime is 15978603241. The next prime is 15978603247. The reversal of 15978603243 is 34230687951.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 34230687951 = 3 ⋅11410229317.

It is not a de Polignac number, because 15978603243 - 2¹ = 15978603241 is a prime.

It is the 126407-th Hogben number.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 15978603192 and 15978603201.

It is not an unprimeable number, because it can be changed into a prime (15978603241) by changing a digit.

It is a nontrivial repunit in base 126406.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2663100538 + ... + 2663100543.

It is an arithmetic number, because the mean of its divisors is an integer number (5326201082).

It is a 2-persistent number, because it is pandigital, and so is 2⋅15978603243 = 31957206486, but 3⋅15978603243 = 47935809729 is not.

Almost surely, 2^15978603243 is an apocalyptic number.

15978603243 is a deficient number, since it is larger than the sum of its proper divisors (5326201085).

15978603243 is an equidigital number, since it uses as much as digits as its factorization.

15978603243 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5326201084.

The product of its (nonzero) digits is 1088640, while the sum is 48.

The spelling of 15978603243 in words is "fifteen billion, nine hundred seventy-eight million, six hundred three thousand, two hundred forty-three".