30720438 has 64 divisors (see below), whose sum is σ = 79249920. Its totient is φ = 8639136.

The previous prime is 30720421. The next prime is 30720457. The reversal of 30720438 is 83402703.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

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 31 ways as a sum of consecutive naturals, for example, 24720 + ... + 25932.

It is an arithmetic number, because the mean of its divisors is an integer number (1238280).

Almost surely, 2^30720438 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 30720438, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39624960).

30720438 is an abundant number, since it is smaller than the sum of its proper divisors (48529482).

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

30720438 is a wasteful number, since it uses less digits than its factorization.

30720438 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1298 (or 1292 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 27.

The square root of 30720438 is about 5542.6020964886. The cubic root of 30720438 is about 313.1908997517.

The spelling of 30720438 in words is "thirty million, seven hundred twenty thousand, four hundred thirty-eight".