18205680 has 80 divisors (see below), whose sum is σ = 58281984. Its totient is φ = 4696320.

The previous prime is 18205619. The next prime is 18205687. The reversal of 18205680 is 8650281.

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

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18205687) 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 15 ways as a sum of consecutive naturals, for example, 6217 + ... + 8663.

Almost surely, 2^18205680 is an apocalyptic number.

18205680 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 18205680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29140992).

18205680 is an abundant number, since it is smaller than the sum of its proper divisors (40076304).

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

18205680 is a wasteful number, since it uses less digits than its factorization.

18205680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2494 (or 2488 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 30.

The square root of 18205680 is about 4266.8114558766. The cubic root of 18205680 is about 263.0685725766.

The spelling of 18205680 in words is "eighteen million, two hundred five thousand, six hundred eighty".