19918368 has 144 divisors (see below), whose sum is σ = 61641216. Its totient is φ = 6082560.

The previous prime is 19918361. The next prime is 19918429. The reversal of 19918368 is 86381991.

It is a Cunningham number, because it is equal to 4463²-1.

It is a tau number, because it is divible by the number of its divisors (144).

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (19918361) 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 23 ways as a sum of consecutive naturals, for example, 205296 + ... + 205392.

It is an arithmetic number, because the mean of its divisors is an integer number (428064).

Almost surely, 2^19918368 is an apocalyptic number.

19918368 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 19918368, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30820608).

19918368 is an abundant number, since it is smaller than the sum of its proper divisors (41722848).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

19918368 is a wasteful number, since it uses less digits than its factorization.

19918368 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 167 (or 156 counting only the distinct ones).

The product of its digits is 93312, while the sum is 45.

The square root of 19918368 is about 4462.9998879677. Note that the first 3 decimals coincide. The cubic root of 19918368 is about 271.0719524997.

The spelling of 19918368 in words is "nineteen million, nine hundred eighteen thousand, three hundred sixty-eight".