305840 has 20 divisors (see below), whose sum is σ = 711264. Its totient is φ = 122304.

The previous prime is 305839. The next prime is 305849. The reversal of 305840 is 48503.

It is a tau number, because it is divible by the number of its divisors (20).

It is a Harshad number since it is a multiple of its sum of digits (20).

It is an Ulam number.

It is not an unprimeable number, because it can be changed into a prime (305849) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1832 + ... + 1991.

2³⁰⁵⁸⁴⁰ is an apocalyptic number.

It is an amenable number.

305840 is an abundant number, since it is smaller than the sum of its proper divisors (405424).

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

305840 is a wasteful number, since it uses less digits than its factorization.

305840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3836 (or 3830 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 20.

The square root of 305840 is about 553.0280282228. The cubic root of 305840 is about 67.3748940121.

The spelling of 305840 in words is "three hundred five thousand, eight hundred forty".