138691471 has 8 divisors (see below), whose sum is σ = 141048864. Its totient is φ = 136345440.

The previous prime is 138691453. The next prime is 138691481. The reversal of 138691471 is 174196831.

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

It is a cyclic number.

It is not a de Polignac number, because 138691471 - 2⁵ = 138691439 is a prime.

It is a super-3 number, since 3×138691471³ (a number of 25 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138691481) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 23865 + ... + 29101.

It is an arithmetic number, because the mean of its divisors is an integer number (17631108).

Almost surely, 2^138691471 is an apocalyptic number.

138691471 is a deficient number, since it is larger than the sum of its proper divisors (2357393).

138691471 is an equidigital number, since it uses as much as digits as its factorization.

138691471 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5681.

The product of its digits is 36288, while the sum is 40.

The square root of 138691471 is about 11776.7343096463. The cubic root of 138691471 is about 517.6265986644.

The spelling of 138691471 in words is "one hundred thirty-eight million, six hundred ninety-one thousand, four hundred seventy-one".