30720138 has 32 divisors (see below), whose sum is σ = 64022400. Its totient is φ = 9817920.

The previous prime is 30720127. The next prime is 30720143. The reversal of 30720138 is 83102703.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 14788 + ... + 16736.

It is an arithmetic number, because the mean of its divisors is an integer number (2000700).

Almost surely, 2^30720138 is an apocalyptic number.

30720138 is an abundant number, since it is smaller than the sum of its proper divisors (33302262).

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

30720138 is a wasteful number, since it uses less digits than its factorization.

30720138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2062.

The product of its (nonzero) digits is 1008, while the sum is 24.

The square root of 30720138 is about 5542.5750333216. The cubic root of 30720138 is about 313.1898802613.

The spelling of 30720138 in words is "thirty million, seven hundred twenty thousand, one hundred thirty-eight".