138420 has 36 divisors (see below), whose sum is σ = 420420. Its totient is φ = 36864.

The previous prime is 138407. The next prime is 138427. The reversal of 138420 is 24831.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 51984 + 86436 = 228^2 + 294^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 138393 and 138402.

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 in 11 ways as a sum of consecutive naturals, for example, 205 + ... + 564.

2¹³⁸⁴²⁰ is an apocalyptic number.

138420 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

138420 is an abundant number, since it is smaller than the sum of its proper divisors (282000).

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

138420 is a wasteful number, since it uses less digits than its factorization.

138420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 784 (or 779 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

The square root of 138420 is about 372.0483839503. The cubic root of 138420 is about 51.7288648554.

The spelling of 138420 in words is "one hundred thirty-eight thousand, four hundred twenty".