30720839 has 4 divisors (see below), whose sum is σ = 30763824. Its totient is φ = 30677856.

The previous prime is 30720803. The next prime is 30720857. The reversal of 30720839 is 93802703.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 30720839 - 2²⁴ = 13943623 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (30720539) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20402 + ... + 21855.

It is an arithmetic number, because the mean of its divisors is an integer number (7690956).

Almost surely, 2^30720839 is an apocalyptic number.

30720839 is a deficient number, since it is larger than the sum of its proper divisors (42985).

30720839 is an equidigital number, since it uses as much as digits as its factorization.

30720839 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42984.

The product of its (nonzero) digits is 9072, while the sum is 32.

The square root of 30720839 is about 5542.6382707155. The cubic root of 30720839 is about 313.1922624602.

The spelling of 30720839 in words is "thirty million, seven hundred twenty thousand, eight hundred thirty-nine".