18921340 has 96 divisors (see below), whose sum is σ = 46267200. Its totient is φ = 6451200.

The previous prime is 18921337. The next prime is 18921347. The reversal of 18921340 is 4312981.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 18921299 and 18921308.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18921347) 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 31 ways as a sum of consecutive naturals, for example, 187290 + ... + 187390.

It is an arithmetic number, because the mean of its divisors is an integer number (481950).

Almost surely, 2^18921340 is an apocalyptic number.

18921340 is a gapful number since it is divisible by the number (10) 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 18921340, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23133600).

18921340 is an abundant number, since it is smaller than the sum of its proper divisors (27345860).

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

18921340 is a wasteful number, since it uses less digits than its factorization.

18921340 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 175 (or 173 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 28.

The square root of 18921340 is about 4349.8666646232. The cubic root of 18921340 is about 266.4714161022.

The spelling of 18921340 in words is "eighteen million, nine hundred twenty-one thousand, three hundred forty".