18380820 has 24 divisors (see below), whose sum is σ = 51466464. Its totient is φ = 4901536.

The previous prime is 18380819. The next prime is 18380827. The reversal of 18380820 is 2808381.

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 (18380827) 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, 153114 + ... + 153233.

It is an arithmetic number, because the mean of its divisors is an integer number (2144436).

Almost surely, 2^18380820 is an apocalyptic number.

18380820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18380820 is an abundant number, since it is smaller than the sum of its proper divisors (33085644).

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

18380820 is a wasteful number, since it uses less digits than its factorization.

18380820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 306359 (or 306357 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 30.

The square root of 18380820 is about 4287.2858547104. The cubic root of 18380820 is about 263.9094616074.

It can be divided in two parts, 183 and 80820, that added together give a triangular number (81003 = T₄₀₂).

The spelling of 18380820 in words is "eighteen million, three hundred eighty thousand, eight hundred twenty".