138021293 has 8 divisors (see below), whose sum is σ = 141542520. Its totient is φ = 134507520.

The previous prime is 138021287. The next prime is 138021307. The reversal of 138021293 is 392120831.

It can be written as a sum of positive squares in 4 ways, for example, as 13520329 + 124500964 = 3677^2 + 11158^2 .

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-138021293 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138021193) 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, 67421 + ... + 69437.

It is an arithmetic number, because the mean of its divisors is an integer number (17692815).

Almost surely, 2^138021293 is an apocalyptic number.

It is an amenable number.

138021293 is a deficient number, since it is larger than the sum of its proper divisors (3521227).

138021293 is a wasteful number, since it uses less digits than its factorization.

138021293 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3727.

The product of its (nonzero) digits is 2592, while the sum is 29.

The square root of 138021293 is about 11748.2463797794. The cubic root of 138021293 is about 516.7915023129.

The spelling of 138021293 in words is "one hundred thirty-eight million, twenty-one thousand, two hundred ninety-three".