18504220 has 24 divisors (see below), whose sum is σ = 44410464. Its totient is φ = 6344256.

The previous prime is 18504217. The next prime is 18504223. The reversal of 18504220 is 2240581.

It is an interprime number because it is at equal distance from previous prime (18504217) and next prime (18504223).

It is a junction number, because it is equal to n+sod(n) for n = 18504191 and 18504200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18504223) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 65947 + ... + 66226.

It is an arithmetic number, because the mean of its divisors is an integer number (1850436).

Almost surely, 2^18504220 is an apocalyptic number.

18504220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18504220 is an abundant number, since it is smaller than the sum of its proper divisors (25906244).

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

18504220 is a wasteful number, since it uses less digits than its factorization.

18504220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 132189 (or 132187 counting only the distinct ones).

The product of its (nonzero) digits is 640, while the sum is 22.

The square root of 18504220 is about 4301.6531705845. The cubic root of 18504220 is about 264.4987320120.

The spelling of 18504220 in words is "eighteen million, five hundred four thousand, two hundred twenty".