18519840 has 120 divisors (see below), whose sum is σ = 65405340. Its totient is φ = 4935168.

The previous prime is 18519829. The next prime is 18519841. The reversal of 18519840 is 4891581.

It can be written as a sum of positive squares in 2 ways, for example, as 16548624 + 1971216 = 4068^2 + 1404^2 .

It is a tau number, because it is divible by the number of its divisors (120).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 18519795 and 18519804.

It is not an unprimeable number, because it can be changed into a prime (18519841) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 12246 + ... + 13674.

Almost surely, 2^18519840 is an apocalyptic number.

18519840 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 18519840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32702670).

18519840 is an abundant number, since it is smaller than the sum of its proper divisors (46885500).

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

18519840 is a wasteful number, since it uses less digits than its factorization.

18519840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1456 (or 1439 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 36.

The square root of 18519840 is about 4303.4683686534. The cubic root of 18519840 is about 264.5731350083.

The spelling of 18519840 in words is "eighteen million, five hundred nineteen thousand, eight hundred forty".