138909851 has 4 divisors (see below), whose sum is σ = 138933432. Its totient is φ = 138886272.

The previous prime is 138909847. The next prime is 138909899. The reversal of 138909851 is 158909831.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 138909851 - 2² = 138909847 is a prime.

It is a super-4 number, since 4×138909851⁴ (a number of 34 digits) contains 4444 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (138909151) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 5435 + ... + 17531.

It is an arithmetic number, because the mean of its divisors is an integer number (34733358).

Almost surely, 2^138909851 is an apocalyptic number.

138909851 is a deficient number, since it is larger than the sum of its proper divisors (23581).

138909851 is a wasteful number, since it uses less digits than its factorization.

138909851 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23580.

The product of its (nonzero) digits is 77760, while the sum is 44.

The square root of 138909851 is about 11786.0023332765. The cubic root of 138909851 is about 517.8981366762.

The spelling of 138909851 in words is "one hundred thirty-eight million, nine hundred nine thousand, eight hundred fifty-one".