30021640 has 96 divisors (see below), whose sum is σ = 77215680. Its totient is φ = 10416000.

The previous prime is 30021631. The next prime is 30021661. The reversal of 30021640 is 4612003.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 422805 + ... + 422875.

It is an arithmetic number, because the mean of its divisors is an integer number (804330).

Almost surely, 2^30021640 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 30021640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38607840).

30021640 is an abundant number, since it is smaller than the sum of its proper divisors (47194040).

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

30021640 is a wasteful number, since it uses less digits than its factorization.

30021640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 155 (or 120 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 16.

The square root of 30021640 is about 5479.2006716309. The cubic root of 30021640 is about 310.7979443179.

Adding to 30021640 its reverse (4612003), we get a palindrome (34633643).

The spelling of 30021640 in words is "thirty million, twenty-one thousand, six hundred forty".