18331920 has 240 divisors, whose sum is σ = 68245632. Its totient is φ = 4561920.

The previous prime is 18331913. The next prime is 18331939. The reversal of 18331920 is 2913381.

It is a tau number, because it is divible by the number of its divisors (240).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 447100 + ... + 447140.

Almost surely, 2^18331920 is an apocalyptic number.

18331920 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 18331920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34122816).

18331920 is an abundant number, since it is smaller than the sum of its proper divisors (49913712).

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

18331920 is a wasteful number, since it uses less digits than its factorization.

18331920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 92 (or 74 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 27.

The square root of 18331920 is about 4281.5791479313. The cubic root of 18331920 is about 263.6752204464.

The spelling of 18331920 in words is "eighteen million, three hundred thirty-one thousand, nine hundred twenty".