138501421 has 4 divisors (see below), whose sum is σ = 138938652. Its totient is φ = 138064192.

The previous prime is 138501373. The next prime is 138501437. The reversal of 138501421 is 124105831.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 25908100 + 112593321 = 5090^2 + 10611^2 .

It is a cyclic number.

It is not a de Polignac number, because 138501421 - 2²⁷ = 4283693 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138501481) 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, 218140 + ... + 218773.

It is an arithmetic number, because the mean of its divisors is an integer number (34734663).

Almost surely, 2^138501421 is an apocalyptic number.

It is an amenable number.

138501421 is a deficient number, since it is larger than the sum of its proper divisors (437231).

138501421 is an equidigital number, since it uses as much as digits as its factorization.

138501421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 437230.

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

The square root of 138501421 is about 11768.6626682899. The cubic root of 138501421 is about 517.3900546692.

The spelling of 138501421 in words is "one hundred thirty-eight million, five hundred one thousand, four hundred twenty-one".