138524840 has 32 divisors (see below), whose sum is σ = 330016680. Its totient is φ = 52150272.

The previous prime is 138524831. The next prime is 138524843. The reversal of 138524840 is 48425831.

It can be written as a sum of positive squares in 4 ways, for example, as 120868036 + 17656804 = 10994^2 + 4202^2 .

It is a Smith number, since the sum of its digits (35) coincides with the sum of the digits of its prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 138524840.

It is not an unprimeable number, because it can be changed into a prime (138524843) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 101177 + ... + 102536.

Almost surely, 2^138524840 is an apocalyptic number.

138524840 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

138524840 is an abundant number, since it is smaller than the sum of its proper divisors (191491840).

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

138524840 is a wasteful number, since it uses less digits than its factorization.

138524840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 203741 (or 203737 counting only the distinct ones).

The product of its (nonzero) digits is 30720, while the sum is 35.

The square root of 138524840 is about 11769.6575990978. The cubic root of 138524840 is about 517.4192145982.

Subtracting from 138524840 its reverse (48425831), we obtain a palindrome (90099009).

The spelling of 138524840 in words is "one hundred thirty-eight million, five hundred twenty-four thousand, eight hundred forty".