198668519651 has 4 divisors (see below), whose sum is σ = 227049736752. Its totient is φ = 170287302552.

The previous prime is 198668519617. The next prime is 198668519669. The reversal of 198668519651 is 156915866891.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 198668519651 - 2¹⁸ = 198668257507 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (198668519611) 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, 14190608540 + ... + 14190608553.

It is an arithmetic number, because the mean of its divisors is an integer number (56762434188).

Almost surely, 2^198668519651 is an apocalyptic number.

198668519651 is a deficient number, since it is larger than the sum of its proper divisors (28381217101).

198668519651 is an equidigital number, since it uses as much as digits as its factorization.

198668519651 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28381217100.

The product of its digits is 27993600, while the sum is 65.

The spelling of 198668519651 in words is "one hundred ninety-eight billion, six hundred sixty-eight million, five hundred nineteen thousand, six hundred fifty-one".