138988506 has 16 divisors (see below), whose sum is σ = 280576224. Its totient is φ = 45896304.

The previous prime is 138988459. The next prime is 138988559. The reversal of 138988506 is 605889831.

It is a super-2 number, since 2×138988506² = 38635609600224072, which contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 107605 + ... + 108888.

It is an arithmetic number, because the mean of its divisors is an integer number (17536014).

Almost surely, 2^138988506 is an apocalyptic number.

138988506 is an abundant number, since it is smaller than the sum of its proper divisors (141587718).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

138988506 is a wasteful number, since it uses less digits than its factorization.

138988506 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 216605.

The product of its (nonzero) digits is 414720, while the sum is 48.

The square root of 138988506 is about 11789.3386582963. The cubic root of 138988506 is about 517.9958681463.

The spelling of 138988506 in words is "one hundred thirty-eight million, nine hundred eighty-eight thousand, five hundred six".