30721808 has 40 divisors (see below), whose sum is σ = 64662528. Its totient is φ = 14055552.

The previous prime is 30721799. The next prime is 30721829. The reversal of 30721808 is 80812703.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 25835 + ... + 26997.

Almost surely, 2^30721808 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 30721808, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32331264).

30721808 is an abundant number, since it is smaller than the sum of its proper divisors (33940720).

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

30721808 is a wasteful number, since it uses less digits than its factorization.

30721808 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1311 (or 1305 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 29.

The square root of 30721808 is about 5542.7256832717. The cubic root of 30721808 is about 313.1955553402.

The spelling of 30721808 in words is "thirty million, seven hundred twenty-one thousand, eight hundred eight".