138078749 has 4 divisors (see below), whose sum is σ = 138113664. Its totient is φ = 138043836.

The previous prime is 138078667. The next prime is 138078751. The reversal of 138078749 is 947870831.

138078749 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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: 947870831 = 997 ⋅950723.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-138078749 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138078769) 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, 10637 + ... + 19730.

It is an arithmetic number, because the mean of its divisors is an integer number (34528416).

Almost surely, 2^138078749 is an apocalyptic number.

It is an amenable number.

138078749 is a deficient number, since it is larger than the sum of its proper divisors (34915).

138078749 is an equidigital number, since it uses as much as digits as its factorization.

138078749 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34914.

The product of its (nonzero) digits is 338688, while the sum is 47.

The square root of 138078749 is about 11750.6914264651. The cubic root of 138078749 is about 516.8632029726.

The spelling of 138078749 in words is "one hundred thirty-eight million, seventy-eight thousand, seven hundred forty-nine".