30640 has 20 divisors (see below), whose sum is σ = 71424. Its totient is φ = 12224.

The previous prime is 30637. The next prime is 30643. The reversal of 30640 is 4603.

30640 is nontrivially palindromic in base 3.

It is an interprime number because it is at equal distance from previous prime (30637) and next prime (30643).

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

It is a self number, because there is not a number n which added to its sum of digits gives 30640.

It is not an unprimeable number, because it can be changed into a prime (30643) 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, 112 + ... + 271.

2³⁰⁶⁴⁰ is an apocalyptic number.

It is an amenable number.

30640 is an abundant number, since it is smaller than the sum of its proper divisors (40784).

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

It is a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35712).

30640 is a wasteful number, since it uses less digits than its factorization.

30640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 396 (or 390 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 13.

The square root of 30640 is about 175.0428518963. The cubic root of 30640 is about 31.2917309148.

The spelling of 30640 in words is "thirty thousand, six hundred forty".