138243425618 has 4 divisors (see below), whose sum is σ = 207365138430. Its totient is φ = 69121712808.

The previous prime is 138243425591. The next prime is 138243425623. The reversal of 138243425618 is 816524342831.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 816524342831 = 93187 ⋅8762213.

It can be written as a sum of positive squares in only one way, i.e., 75606851089 + 62636574529 = 274967^2 + 250273^2 .

It is a super-2 number, since 2×138243425618² (a number of 23 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 34560856403 + ... + 34560856406.

Almost surely, 2^138243425618 is an apocalyptic number.

138243425618 is a deficient number, since it is larger than the sum of its proper divisors (69121712812).

138243425618 is an equidigital number, since it uses as much as digits as its factorization.

138243425618 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 69121712811.

The product of its digits is 1105920, while the sum is 47.

The spelling of 138243425618 in words is "one hundred thirty-eight billion, two hundred forty-three million, four hundred twenty-five thousand, six hundred eighteen".