138628505 has 8 divisors (see below), whose sum is σ = 166763400. Its totient is φ = 110630016.

The previous prime is 138628493. The next prime is 138628547. The reversal of 138628505 is 505826831.

It can be written as a sum of positive squares in 4 ways, for example, as 74580496 + 64048009 = 8636^2 + 8003^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 138628505 - 2¹⁰ = 138627481 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 31850 + ... + 35939.

It is an arithmetic number, because the mean of its divisors is an integer number (20845425).

Almost surely, 2^138628505 is an apocalyptic number.

It is an amenable number.

138628505 is a deficient number, since it is larger than the sum of its proper divisors (28134895).

138628505 is an equidigital number, since it uses as much as digits as its factorization.

138628505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 68203.

The product of its (nonzero) digits is 57600, while the sum is 38.

The square root of 138628505 is about 11774.0606844028. The cubic root of 138628505 is about 517.5482525584.

The spelling of 138628505 in words is "one hundred thirty-eight million, six hundred twenty-eight thousand, five hundred five".