18991698406 has 8 divisors (see below), whose sum is σ = 29986892280. Its totient is φ = 8996067648.

The previous prime is 18991698377. The next prime is 18991698409. The reversal of 18991698406 is 60489619981.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18991698409) 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, 249890731 + ... + 249890806.

It is an arithmetic number, because the mean of its divisors is an integer number (3748361535).

Almost surely, 2^18991698406 is an apocalyptic number.

18991698406 is a deficient number, since it is larger than the sum of its proper divisors (10995193874).

18991698406 is a wasteful number, since it uses less digits than its factorization.

18991698406 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 499781558.

The product of its (nonzero) digits is 6718464, while the sum is 61.

The spelling of 18991698406 in words is "eighteen billion, nine hundred ninety-one million, six hundred ninety-eight thousand, four hundred six".