19890918 has 24 divisors (see below), whose sum is σ = 45632808. Its totient is φ = 6240192.

The previous prime is 19890911. The next prime is 19890919. The reversal of 19890918 is 81909891.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19890911) 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 11 ways as a sum of consecutive naturals, for example, 32196 + ... + 32807.

It is an arithmetic number, because the mean of its divisors is an integer number (1901367).

Almost surely, 2^19890918 is an apocalyptic number.

19890918 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

19890918 is an abundant number, since it is smaller than the sum of its proper divisors (25741890).

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

19890918 is a wasteful number, since it uses less digits than its factorization.

19890918 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 65028 (or 65025 counting only the distinct ones).

The product of its (nonzero) digits is 46656, while the sum is 45.

The square root of 19890918 is about 4459.9235419455. The cubic root of 19890918 is about 270.9473715787.

The spelling of 19890918 in words is "nineteen million, eight hundred ninety thousand, nine hundred eighteen".