18081520 has 40 divisors (see below), whose sum is σ = 42586560. Its totient is φ = 7138560.

The previous prime is 18081461. The next prime is 18081527. The reversal of 18081520 is 2518081.

It is a tau number, because it is divible by the number of its divisors (40).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18081527) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4890 + ... + 7750.

It is an arithmetic number, because the mean of its divisors is an integer number (1064664).

Almost surely, 2^18081520 is an apocalyptic number.

18081520 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 18081520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21293280).

18081520 is an abundant number, since it is smaller than the sum of its proper divisors (24505040).

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

18081520 is a wasteful number, since it uses less digits than its factorization.

18081520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2953 (or 2947 counting only the distinct ones).

The product of its (nonzero) digits is 640, while the sum is 25.

The square root of 18081520 is about 4252.2370583024. The cubic root of 18081520 is about 262.4691785430.

The spelling of 18081520 in words is "eighteen million, eighty-one thousand, five hundred twenty".