18280640 has 56 divisors (see below), whose sum is σ = 49755552. Its totient is φ = 6266880.

The previous prime is 18280631. The next prime is 18280651. The reversal of 18280640 is 4608281.

It is a tau number, because it is divible by the number of its divisors (56).

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1841 + ... + 6320.

It is an arithmetic number, because the mean of its divisors is an integer number (888492).

Almost surely, 2^18280640 is an apocalyptic number.

18280640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18280640 is an abundant number, since it is smaller than the sum of its proper divisors (31474912).

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

18280640 is an equidigital number, since it uses as much as digits as its factorization.

18280640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8185 (or 8175 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 29.

The square root of 18280640 is about 4275.5865094745. The cubic root of 18280640 is about 263.4291306998.

The spelling of 18280640 in words is "eighteen million, two hundred eighty thousand, six hundred forty".