18509140 has 48 divisors (see below), whose sum is σ = 42173712. Its totient is φ = 6782976.

The previous prime is 18509129. The next prime is 18509143. The reversal of 18509140 is 4190581.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 242064 + 18267076 = 492^2 + 4274^2 .

It is a junction number, because it is equal to n+sod(n) for n = 18509099 and 18509108.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18509143) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 66682 + ... + 66958.

It is an arithmetic number, because the mean of its divisors is an integer number (878619).

Almost surely, 2^18509140 is an apocalyptic number.

18509140 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 18509140, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21086856).

18509140 is an abundant number, since it is smaller than the sum of its proper divisors (23664572).

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

18509140 is a wasteful number, since it uses less digits than its factorization.

18509140 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 556 (or 554 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 28.

The square root of 18509140 is about 4302.2250057383. The cubic root of 18509140 is about 264.5221720425.

The spelling of 18509140 in words is "eighteen million, five hundred nine thousand, one hundred forty".