18991982 has 32 divisors (see below), whose sum is σ = 31363200. Its totient is φ = 8594208.

The previous prime is 18991981. The next prime is 18992027. The reversal of 18991982 is 28919981.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18991981) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 96308 + ... + 96504.

It is an arithmetic number, because the mean of its divisors is an integer number (980100).

Almost surely, 2^18991982 is an apocalyptic number.

18991982 is a deficient number, since it is larger than the sum of its proper divisors (12371218).

18991982 is a wasteful number, since it uses less digits than its factorization.

18991982 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 320.

The product of its digits is 93312, while the sum is 47.

The square root of 18991982 is about 4357.9791188118. The cubic root of 18991982 is about 266.8026240744.

The spelling of 18991982 in words is "eighteen million, nine hundred ninety-one thousand, nine hundred eighty-two".