18991360 has 72 divisors (see below), whose sum is σ = 46836216. Its totient is φ = 7372800.

The previous prime is 18991319. The next prime is 18991361. The reversal of 18991360 is 6319981.

It can be written as a sum of positive squares in 4 ways, for example, as 11505664 + 7485696 = 3392^2 + 2736^2 .

It is a Harshad number since it is a multiple of its sum of digits (37).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18991361) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 47160 + ... + 47560.

It is an arithmetic number, because the mean of its divisors is an integer number (650503).

Almost surely, 2^18991360 is an apocalyptic number.

18991360 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 18991360, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23418108).

18991360 is an abundant number, since it is smaller than the sum of its proper divisors (27844856).

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

18991360 is an equidigital number, since it uses as much as digits as its factorization.

18991360 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 459 (or 445 counting only the distinct ones).

The product of its (nonzero) digits is 11664, while the sum is 37.

The square root of 18991360 is about 4357.9077548750. The cubic root of 18991360 is about 266.7997113884.

The spelling of 18991360 in words is "eighteen million, nine hundred ninety-one thousand, three hundred sixty".