138942769 has 4 divisors (see below), whose sum is σ = 158791744. Its totient is φ = 119093796.

The previous prime is 138942767. The next prime is 138942779. The reversal of 138942769 is 967249831.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 967249831 = 101 ⋅9576731.

It is a cyclic number.

It is not a de Polignac number, because 138942769 - 2¹ = 138942767 is a prime.

It is a super-2 number, since 2×138942769² = 38610186114774722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (138942767) 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, 9924477 + ... + 9924490.

It is an arithmetic number, because the mean of its divisors is an integer number (39697936).

Almost surely, 2^138942769 is an apocalyptic number.

It is an amenable number.

138942769 is a deficient number, since it is larger than the sum of its proper divisors (19848975).

138942769 is an equidigital number, since it uses as much as digits as its factorization.

138942769 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19848974.

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

The square root of 138942769 is about 11787.3987376350. The cubic root of 138942769 is about 517.9390428809.

The spelling of 138942769 in words is "one hundred thirty-eight million, nine hundred forty-two thousand, seven hundred sixty-nine".