138528640 has 32 divisors (see below), whose sum is σ = 331171560. Its totient is φ = 55411200.

The previous prime is 138528617. The next prime is 138528641. The reversal of 138528640 is 46825831.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (32).

It is a self number, because there is not a number n which added to its sum of digits gives 138528640.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138528641) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 107586 + ... + 108865.

Almost surely, 2^138528640 is an apocalyptic number.

138528640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

138528640 is an abundant number, since it is smaller than the sum of its proper divisors (192642920).

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

138528640 is an equidigital number, since it uses as much as digits as its factorization.

138528640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 216470 (or 216458 counting only the distinct ones).

The product of its (nonzero) digits is 46080, while the sum is 37.

The square root of 138528640 is about 11769.8190300446. The cubic root of 138528640 is about 517.4239458195.

The spelling of 138528640 in words is "one hundred thirty-eight million, five hundred twenty-eight thousand, six hundred forty".