138721242 has 32 divisors (see below), whose sum is σ = 318597120. Its totient is φ = 39823920.

The previous prime is 138721237. The next prime is 138721267. The reversal of 138721242 is 242127831.

138721242 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Smith number, since the sum of its digits (30) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

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, 54058 + ... + 56565.

It is an arithmetic number, because the mean of its divisors is an integer number (9956160).

Almost surely, 2^138721242 is an apocalyptic number.

138721242 is an abundant number, since it is smaller than the sum of its proper divisors (179875878).

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

138721242 is a wasteful number, since it uses less digits than its factorization.

138721242 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 110658.

The product of its digits is 5376, while the sum is 30.

The square root of 138721242 is about 11777.9982170146. The cubic root of 138721242 is about 517.6636332873.

The spelling of 138721242 in words is "one hundred thirty-eight million, seven hundred twenty-one thousand, two hundred forty-two".