138621984 has 72 divisors (see below), whose sum is σ = 373408560. Its totient is φ = 45027840.

The previous prime is 138621983. The next prime is 138621991. The reversal of 138621984 is 489126831.

It is not an unprimeable number, because it can be changed into a prime (138621983) 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, 160947 + ... + 161805.

It is an arithmetic number, because the mean of its divisors is an integer number (5186230).

Almost surely, 2^138621984 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 138621984, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (186704280).

138621984 is an abundant number, since it is smaller than the sum of its proper divisors (234786576).

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

138621984 is an equidigital number, since it uses as much as digits as its factorization.

138621984 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 954 (or 905 counting only the distinct ones).

The product of its digits is 82944, while the sum is 42.

The square root of 138621984 is about 11773.7837588432. The cubic root of 138621984 is about 517.5401373802.

The spelling of 138621984 in words is "one hundred thirty-eight million, six hundred twenty-one thousand, nine hundred eighty-four".