30685440 has 144 divisors (see below), whose sum is σ = 100368576. Its totient is φ = 7987200.

The previous prime is 30685429. The next prime is 30685441. The reversal of 30685440 is 4458603.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 30685398 and 30685407.

It is not an unprimeable number, because it can be changed into a prime (30685441) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 234175 + ... + 234305.

It is an arithmetic number, because the mean of its divisors is an integer number (697004).

Almost surely, 2^30685440 is an apocalyptic number.

30685440 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 30685440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (50184288).

30685440 is an abundant number, since it is smaller than the sum of its proper divisors (69683136).

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

30685440 is a wasteful number, since it uses less digits than its factorization.

30685440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 216 (or 202 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 30.

The square root of 30685440 is about 5539.4440154225. Note that the first 3 decimals coincide. The cubic root of 30685440 is about 313.0719211945.

It can be divided in two parts, 30685 and 440, that added together give a triangular number (31125 = T₂₄₉).

The spelling of 30685440 in words is "thirty million, six hundred eighty-five thousand, four hundred forty".