18780640 has 48 divisors (see below), whose sum is σ = 44824752. Its totient is φ = 7435264.

The previous prime is 18780623. The next prime is 18780667. The reversal of 18780640 is 4608781.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 18780596 and 18780605.

It is a congruent number.

It is an unprimeable number.

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, 16572 + ... + 17668.

It is an arithmetic number, because the mean of its divisors is an integer number (933849).

Almost surely, 2^18780640 is an apocalyptic number.

18780640 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 18780640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22412376).

18780640 is an abundant number, since it is smaller than the sum of its proper divisors (26044112).

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

18780640 is a wasteful number, since it uses less digits than its factorization.

18780640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1219 (or 1211 counting only the distinct ones).

The product of its (nonzero) digits is 10752, while the sum is 34.

The square root of 18780640 is about 4333.6635771596. The cubic root of 18780640 is about 265.8092740242.

The spelling of 18780640 in words is "eighteen million, seven hundred eighty thousand, six hundred forty".