18185820 has 24 divisors (see below), whose sum is σ = 50920464. Its totient is φ = 4849536.

The previous prime is 18185819. The next prime is 18185821. The reversal of 18185820 is 2858181.

It is an interprime number because it is at equal distance from previous prime (18185819) and next prime (18185821).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18185821) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 151489 + ... + 151608.

It is an arithmetic number, because the mean of its divisors is an integer number (2121686).

Almost surely, 2^18185820 is an apocalyptic number.

18185820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18185820 is an abundant number, since it is smaller than the sum of its proper divisors (32734644).

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

18185820 is a wasteful number, since it uses less digits than its factorization.

18185820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 303109 (or 303107 counting only the distinct ones).

The product of its (nonzero) digits is 5120, while the sum is 33.

The square root of 18185820 is about 4264.4835560710. The cubic root of 18185820 is about 262.9728800461.

The spelling of 18185820 in words is "eighteen million, one hundred eighty-five thousand, eight hundred twenty".