19800918 has 12 divisors (see below), whose sum is σ = 42902028. Its totient is φ = 6600300.

The previous prime is 19800899. The next prime is 19800929. The reversal of 19800918 is 81900891.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 550008 + ... + 550043.

It is an arithmetic number, because the mean of its divisors is an integer number (3575169).

Almost surely, 2^19800918 is an apocalyptic number.

19800918 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

19800918 is an abundant number, since it is smaller than the sum of its proper divisors (23101110).

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

19800918 is a wasteful number, since it uses less digits than its factorization.

19800918 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1100059 (or 1100056 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 36.

The square root of 19800918 is about 4449.8222436408. The cubic root of 19800918 is about 270.5381038137.

The spelling of 19800918 in words is "nineteen million, eight hundred thousand, nine hundred eighteen".