138890538 has 28 divisors (see below), whose sum is σ = 312364098. Its totient is φ = 46296360.

The previous prime is 138890533. The next prime is 138890569. The reversal of 138890538 is 835098831.

138890538 is a `hidden beast` number, since 1 + 38 + 89 + 0 + 538 = 666.

It can be written as a sum of positive squares in only one way, i.e., 135419769 + 3470769 = 11637^2 + 1863^2 .

It is a junction number, because it is equal to n+sod(n) for n = 138890493 and 138890502.

It is not an unprimeable number, because it can be changed into a prime (138890533) by changing a digit.

It is a polite number, since it can be written in 13 ways as a sum of consecutive naturals, for example, 46173 + ... + 49088.

Almost surely, 2^138890538 is an apocalyptic number.

138890538 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

138890538 is an abundant number, since it is smaller than the sum of its proper divisors (173473560).

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

138890538 is an frugal number, since it uses more digits than its factorization.

138890538 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 95281 (or 95266 counting only the distinct ones).

The product of its (nonzero) digits is 207360, while the sum is 45.

The square root of 138890538 is about 11785.1829854271. The cubic root of 138890538 is about 517.8741339862.

The spelling of 138890538 in words is "one hundred thirty-eight million, eight hundred ninety thousand, five hundred thirty-eight".