18209380 has 72 divisors (see below), whose sum is σ = 47142648. Its totient is φ = 5870592.

The previous prime is 18209341. The next prime is 18209407. The reversal of 18209380 is 8390281.

It can be written as a sum of positive squares in 4 ways, for example, as 9400356 + 8809024 = 3066^2 + 2968^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 16114 + ... + 17206.

It is an arithmetic number, because the mean of its divisors is an integer number (654759).

Almost surely, 2^18209380 is an apocalyptic number.

18209380 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 18209380, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23571324).

18209380 is an abundant number, since it is smaller than the sum of its proper divisors (28933268).

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

18209380 is a wasteful number, since it uses less digits than its factorization.

18209380 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1133 (or 1124 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 31.

The square root of 18209380 is about 4267.2450128859. The cubic root of 18209380 is about 263.0863927987.

The spelling of 18209380 in words is "eighteen million, two hundred nine thousand, three hundred eighty".