138140521 has 8 divisors (see below), whose sum is σ = 149834664. Its totient is φ = 126842880.

The previous prime is 138140503. The next prime is 138140551. The reversal of 138140521 is 125041831.

It can be written as a sum of positive squares in 4 ways, for example, as 336400 + 137804121 = 580^2 + 11739^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 138140521 - 2⁵ = 138140489 is a prime.

It is not an unprimeable number, because it can be changed into a prime (138140501) 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, 98400 + ... + 99793.

It is an arithmetic number, because the mean of its divisors is an integer number (18729333).

Almost surely, 2^138140521 is an apocalyptic number.

It is an amenable number.

138140521 is a deficient number, since it is larger than the sum of its proper divisors (11694143).

138140521 is a wasteful number, since it uses less digits than its factorization.

138140521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 198251.

The product of its (nonzero) digits is 960, while the sum is 25.

The square root of 138140521 is about 11753.3195736354. The cubic root of 138140521 is about 516.9402674836.

The spelling of 138140521 in words is "one hundred thirty-eight million, one hundred forty thousand, five hundred twenty-one".