998667686018 has 4 divisors (see below), whose sum is σ = 1498001529030. Its totient is φ = 499333843008.

The previous prime is 998667685993. The next prime is 998667686077. The reversal of 998667686018 is 810686766899.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 810686766899 = 31 ⋅26151186029.

It can be written as a sum of positive squares in only one way, i.e., 993317202409 + 5350483609 = 996653^2 + 73147^2 .

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 249666921503 + ... + 249666921506.

Almost surely, 2^998667686018 is an apocalyptic number.

998667686018 is a deficient number, since it is larger than the sum of its proper divisors (499333843012).

998667686018 is a wasteful number, since it uses less digits than its factorization.

998667686018 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 499333843011.

The product of its (nonzero) digits is 376233984, while the sum is 74.

The spelling of 998667686018 in words is "nine hundred ninety-eight billion, six hundred sixty-seven million, six hundred eighty-six thousand, eighteen".