138103721 has 8 divisors (see below), whose sum is σ = 162098880. Its totient is φ = 115175088.

The previous prime is 138103711. The next prime is 138103747. The reversal of 138103721 is 127301831.

138103721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is not a de Polignac number, because 138103721 - 2¹⁴ = 138087337 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (138103711) 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, 266351 + ... + 266868.

It is an arithmetic number, because the mean of its divisors is an integer number (20262360).

Almost surely, 2^138103721 is an apocalyptic number.

It is an amenable number.

138103721 is a deficient number, since it is larger than the sum of its proper divisors (23995159).

138103721 is an equidigital number, since it uses as much as digits as its factorization.

138103721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 533263.

The product of its (nonzero) digits is 1008, while the sum is 26.

The square root of 138103721 is about 11751.7539541976. The cubic root of 138103721 is about 516.8943599029.

The spelling of 138103721 in words is "one hundred thirty-eight million, one hundred three thousand, seven hundred twenty-one".