18805640 has 64 divisors (see below), whose sum is σ = 49420800. Its totient is φ = 6306048.

The previous prime is 18805613. The next prime is 18805643. The reversal of 18805640 is 4650881.

18805640 = T₁₆₀ + T₁₆₁ + ... + T₄₈₈.

18805640 is a modest number, since divided by 5640 gives 1880 as remainder.

It is a junction number, because it is equal to n+sod(n) for n = 18805597 and 18805606.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18805643) 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, 12446 + ... + 13874.

It is an arithmetic number, because the mean of its divisors is an integer number (772200).

Almost surely, 2^18805640 is an apocalyptic number.

18805640 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 18805640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24710400).

18805640 is an abundant number, since it is smaller than the sum of its proper divisors (30615160).

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

18805640 is a wasteful number, since it uses less digits than its factorization.

18805640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1494 (or 1490 counting only the distinct ones).

The product of its (nonzero) digits is 7680, while the sum is 32.

The square root of 18805640 is about 4336.5470134659. The cubic root of 18805640 is about 265.9271664463.

The spelling of 18805640 in words is "eighteen million, eight hundred five thousand, six hundred forty".