138428421 has 16 divisors (see below), whose sum is σ = 196235136. Its totient is φ = 86605376.

The previous prime is 138428419. The next prime is 138428429. The reversal of 138428421 is 124824831.

It is a cyclic number.

It is not a de Polignac number, because 138428421 - 2¹ = 138428419 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138428429) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 15270 + ... + 22583.

It is an arithmetic number, because the mean of its divisors is an integer number (12264696).

Almost surely, 2^138428421 is an apocalyptic number.

It is an amenable number.

138428421 is a deficient number, since it is larger than the sum of its proper divisors (57806715).

138428421 is a wasteful number, since it uses less digits than its factorization.

138428421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37932.

The product of its digits is 12288, while the sum is 33.

The square root of 138428421 is about 11765.5608026137. The cubic root of 138428421 is about 517.2991383657.

The spelling of 138428421 in words is "one hundred thirty-eight million, four hundred twenty-eight thousand, four hundred twenty-one".