138634491 has 8 divisors (see below), whose sum is σ = 184920400. Its totient is φ = 92385792.

The previous prime is 138634487. The next prime is 138634553. The reversal of 138634491 is 194436831.

138634491 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is not a de Polignac number, because 138634491 - 2² = 138634487 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (138634411) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1035 + ... + 16683.

It is an arithmetic number, because the mean of its divisors is an integer number (23115050).

Almost surely, 2^138634491 is an apocalyptic number.

138634491 is a deficient number, since it is larger than the sum of its proper divisors (46285909).

138634491 is a wasteful number, since it uses less digits than its factorization.

138634491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18605.

The product of its digits is 62208, while the sum is 39.

The square root of 138634491 is about 11774.3148845273. The cubic root of 138634491 is about 517.5557017221. Note that the first 3 decimals are identical.

The spelling of 138634491 in words is "one hundred thirty-eight million, six hundred thirty-four thousand, four hundred ninety-one".