138476618821 has 4 divisors (see below), whose sum is σ = 138511867500. Its totient is φ = 138441370144.

The previous prime is 138476618807. The next prime is 138476618831. The reversal of 138476618821 is 128816674831.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 128816674831 = 13 ⋅9908974987.

It can be written as a sum of positive squares in 2 ways, for example, as 77645822500 + 60830796321 = 278650^2 + 246639^2 .

It is a cyclic number.

It is not a de Polignac number, because 138476618821 - 2⁵ = 138476618789 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 (138476618831) 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, 17618446 + ... + 17626303.

It is an arithmetic number, because the mean of its divisors is an integer number (34627966875).

Almost surely, 2^138476618821 is an apocalyptic number.

It is an amenable number.

138476618821 is a deficient number, since it is larger than the sum of its proper divisors (35248679).

138476618821 is an equidigital number, since it uses as much as digits as its factorization.

138476618821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35248678.

The product of its digits is 3096576, while the sum is 55.

The spelling of 138476618821 in words is "one hundred thirty-eight billion, four hundred seventy-six million, six hundred eighteen thousand, eight hundred twenty-one".