138530640 has 80 divisors (see below), whose sum is σ = 435382848. Its totient is φ = 36430848.

The previous prime is 138530621. The next prime is 138530657. The reversal of 138530640 is 46035831.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 138530598 and 138530607.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13567 + ... + 21473.

Almost surely, 2^138530640 is an apocalyptic number.

138530640 is a gapful number since it is divisible by the number (10) 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 138530640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (217691424).

138530640 is an abundant number, since it is smaller than the sum of its proper divisors (296852208).

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

138530640 is a wasteful number, since it uses less digits than its factorization.

138530640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7996 (or 7990 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 30.

The square root of 138530640 is about 11769.9039928115. The cubic root of 138530640 is about 517.4264359013.

The spelling of 138530640 in words is "one hundred thirty-eight million, five hundred thirty thousand, six hundred forty".