138888505 has 16 divisors (see below), whose sum is σ = 192620160. Its totient is φ = 94165632.

The previous prime is 138888493. The next prime is 138888517. The reversal of 138888505 is 505888831.

It is an interprime number because it is at equal distance from previous prime (138888493) and next prime (138888517).

It is a cyclic number.

It is not a de Polignac number, because 138888505 - 2⁵ = 138888473 is a prime.

It is a super-2 number, since 2×138888505² = 38580033642270050, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 19179 + ... + 25408.

It is an arithmetic number, because the mean of its divisors is an integer number (12038760).

Almost surely, 2^138888505 is an apocalyptic number.

It is an amenable number.

138888505 is a deficient number, since it is larger than the sum of its proper divisors (53731655).

138888505 is an equidigital number, since it uses as much as digits as its factorization.

138888505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44688.

The product of its (nonzero) digits is 307200, while the sum is 46.

The square root of 138888505 is about 11785.0967327383. The cubic root of 138888505 is about 517.8716071924.

The spelling of 138888505 in words is "one hundred thirty-eight million, eight hundred eighty-eight thousand, five hundred five".