308640 has 48 divisors (see below), whose sum is σ = 973728. Its totient is φ = 82176.

The previous prime is 308639. The next prime is 308641. The reversal of 308640 is 46803.

It is an interprime number because it is at equal distance from previous prime (308639) and next prime (308641).

It is a tau number, because it is divible by the number of its divisors (48).

It is not an unprimeable number, because it can be changed into a prime (308641) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 159 + ... + 801.

It is an arithmetic number, because the mean of its divisors is an integer number (20286).

2³⁰⁸⁶⁴⁰ is an apocalyptic number.

308640 is a gapful number since it is divisible by the number (30) 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 308640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (486864).

308640 is an abundant number, since it is smaller than the sum of its proper divisors (665088).

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

308640 is a wasteful number, since it uses less digits than its factorization.

308640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 661 (or 653 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 21.

The square root of 308640 is about 555.5537777749. The cubic root of 308640 is about 67.5798780020.

The spelling of 308640 in words is "three hundred eight thousand, six hundred forty".