138628877 has 4 divisors (see below), whose sum is σ = 139403520. Its totient is φ = 137854236.

The previous prime is 138628873. The next prime is 138628891. The reversal of 138628877 is 778826831.

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.

It is a cyclic number.

It is not a de Polignac number, because 138628877 - 2² = 138628873 is a prime.

It is a super-2 number, since 2×138628877² = 38435931076562258, 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 (138628873) 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, 387053 + ... + 387410.

It is an arithmetic number, because the mean of its divisors is an integer number (34850880).

Almost surely, 2^138628877 is an apocalyptic number.

It is an amenable number.

138628877 is a deficient number, since it is larger than the sum of its proper divisors (774643).

138628877 is an equidigital number, since it uses as much as digits as its factorization.

138628877 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 774642.

The product of its digits is 903168, while the sum is 50.

The square root of 138628877 is about 11774.0764818308. The cubic root of 138628877 is about 517.5487154930.

The spelling of 138628877 in words is "one hundred thirty-eight million, six hundred twenty-eight thousand, eight hundred seventy-seven".