18213520 has 80 divisors (see below), whose sum is σ = 46372032. Its totient is φ = 6612480.

The previous prime is 18213499. The next prime is 18213551. The reversal of 18213520 is 2531281.

It is a tau number, because it is divible by the number of its divisors (80).

It is a junction number, because it is equal to n+sod(n) for n = 18213491 and 18213500.

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 15 ways as a sum of consecutive naturals, for example, 86215 + ... + 86425.

Almost surely, 2^18213520 is an apocalyptic number.

18213520 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 18213520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23186016).

18213520 is an abundant number, since it is smaller than the sum of its proper divisors (28158512).

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

18213520 is a wasteful number, since it uses less digits than its factorization.

18213520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 320 (or 314 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 22.

The square root of 18213520 is about 4267.7300758131. The cubic root of 18213520 is about 263.1063293211.

The spelling of 18213520 in words is "eighteen million, two hundred thirteen thousand, five hundred twenty".