138249679 has 4 divisors (see below), whose sum is σ = 138455776. Its totient is φ = 138043584.

The previous prime is 138249673. The next prime is 138249691. The reversal of 138249679 is 976942831.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 976942831 = 1409 ⋅693359.

It is a cyclic number.

It is not a de Polignac number, because 138249679 - 2¹⁹ = 137725391 is a prime.

It is a super-2 number, since 2×138249679² = 38225947487206082, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138249673) 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, 102039 + ... + 103384.

It is an arithmetic number, because the mean of its divisors is an integer number (34613944).

Almost surely, 2^138249679 is an apocalyptic number.

138249679 is a deficient number, since it is larger than the sum of its proper divisors (206097).

138249679 is an equidigital number, since it uses as much as digits as its factorization.

138249679 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 206096.

The product of its digits is 653184, while the sum is 49.

The square root of 138249679 is about 11757.9623659884. The cubic root of 138249679 is about 517.0763929032.

The spelling of 138249679 in words is "one hundred thirty-eight million, two hundred forty-nine thousand, six hundred seventy-nine".