138212928 has 252 divisors, whose sum is σ = 474299280. Its totient is φ = 38352384.

The previous prime is 138212917. The next prime is 138212929. The reversal of 138212928 is 829212831.

It is a tau number, because it is divible by the number of its divisors (252).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a nude number because it is divisible by every one of its digits.

It is a junction number, because it is equal to n+sod(n) for n = 138212892 and 138212901.

It is not an unprimeable number, because it can be changed into a prime (138212929) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 1665175 + ... + 1665257.

It is an arithmetic number, because the mean of its divisors is an integer number (1882140).

Almost surely, 2^138212928 is an apocalyptic number.

138212928 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 138212928, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (237149640).

138212928 is an abundant number, since it is smaller than the sum of its proper divisors (336086352).

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

138212928 is a wasteful number, since it uses less digits than its factorization.

138212928 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 174 (or 154 counting only the distinct ones).

The product of its digits is 13824, while the sum is 36.

The square root of 138212928 is about 11756.3994488108. The cubic root of 138212928 is about 517.0305705940.

The spelling of 138212928 in words is "one hundred thirty-eight million, two hundred twelve thousand, nine hundred twenty-eight".