138663890 has 8 divisors (see below), whose sum is σ = 249595020. Its totient is φ = 55465552.

The previous prime is 138663887. The next prime is 138663907. The reversal of 138663890 is 98366831.

138663890 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 138462289 + 201601 = 11767^2 + 449^2 .

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

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6933185 + ... + 6933204.

Almost surely, 2^138663890 is an apocalyptic number.

138663890 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

138663890 is a deficient number, since it is larger than the sum of its proper divisors (110931130).

138663890 is a wasteful number, since it uses less digits than its factorization.

138663890 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13866396.

The product of its (nonzero) digits is 186624, while the sum is 44.

The square root of 138663890 is about 11775.5632561674. The cubic root of 138663890 is about 517.5922836350.

The spelling of 138663890 in words is "one hundred thirty-eight million, six hundred sixty-three thousand, eight hundred ninety".