138428 has 6 divisors (see below), whose sum is σ = 242256. Its totient is φ = 69212.

The previous prime is 138427. The next prime is 138433. The reversal of 138428 is 824831.

138428 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×138428² = 38324622368, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 138397 and 138406.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138427) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 17300 + ... + 17307.

It is an arithmetic number, because the mean of its divisors is an integer number (40376).

2¹³⁸⁴²⁸ is an apocalyptic number.

It is an amenable number.

138428 is a deficient number, since it is larger than the sum of its proper divisors (103828).

138428 is a wasteful number, since it uses less digits than its factorization.

138428 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34611 (or 34609 counting only the distinct ones).

The product of its digits is 1536, while the sum is 26.

The square root of 138428 is about 372.0591350847. The cubic root of 138428 is about 51.7298613948.

The spelling of 138428 in words is "one hundred thirty-eight thousand, four hundred twenty-eight".