16631218979 has 4 divisors (see below), whose sum is σ = 16641221376. Its totient is φ = 16621216584.

The previous prime is 16631218969. The next prime is 16631218987. The reversal of 16631218979 is 97981213661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 97981213661 = 277 ⋅353722793.

It is a cyclic number.

It is not a de Polignac number, because 16631218979 - 2⁴ = 16631218963 is a prime.

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 16631218979.

It is not an unprimeable number, because it can be changed into a prime (16631218969) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4998704 + ... + 5002029.

It is an arithmetic number, because the mean of its divisors is an integer number (4160305344).

Almost surely, 2^16631218979 is an apocalyptic number.

16631218979 is a deficient number, since it is larger than the sum of its proper divisors (10002397).

16631218979 is a wasteful number, since it uses less digits than its factorization.

16631218979 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10002396.

The product of its digits is 979776, while the sum is 53.

The spelling of 16631218979 in words is "sixteen billion, six hundred thirty-one million, two hundred eighteen thousand, nine hundred seventy-nine".