30690640 has 20 divisors (see below), whose sum is σ = 71355924. Its totient is φ = 12276224.

The previous prime is 30690637. The next prime is 30690641. The reversal of 30690640 is 4609603.

It can be written as a sum of positive squares in 2 ways, for example, as 12645136 + 18045504 = 3556^2 + 4248^2 .

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

It is a junction number, because it is equal to n+sod(n) for n = 30690599 and 30690608.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (30690641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 191737 + ... + 191896.

Almost surely, 2^30690640 is an apocalyptic number.

It is an amenable number.

30690640 is an abundant number, since it is smaller than the sum of its proper divisors (40665284).

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

30690640 is a wasteful number, since it uses less digits than its factorization.

30690640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 383646 (or 383640 counting only the distinct ones).

The product of its (nonzero) digits is 3888, while the sum is 28.

The square root of 30690640 is about 5539.9133567232. The cubic root of 30690640 is about 313.0896047391.

The spelling of 30690640 in words is "thirty million, six hundred ninety thousand, six hundred forty".