138878857 has 8 divisors (see below), whose sum is σ = 149657984. Its totient is φ = 128113488.

The previous prime is 138878819. The next prime is 138878867. The reversal of 138878857 is 758878831.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-138878857 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 138878798 and 138878807.

It is not an unprimeable number, because it can be changed into a prime (138878867) 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 7 ways as a sum of consecutive naturals, for example, 28738 + ... + 33220.

It is an arithmetic number, because the mean of its divisors is an integer number (18707248).

Almost surely, 2^138878857 is an apocalyptic number.

It is an amenable number.

138878857 is a deficient number, since it is larger than the sum of its proper divisors (10779127).

138878857 is a wasteful number, since it uses less digits than its factorization.

138878857 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6879.

The product of its digits is 3010560, while the sum is 55.

The square root of 138878857 is about 11784.6873950903. The cubic root of 138878857 is about 517.8596154609.

The spelling of 138878857 in words is "one hundred thirty-eight million, eight hundred seventy-eight thousand, eight hundred fifty-seven".