2138257878 has 8 divisors (see below), whose sum is σ = 4276515768. Its totient is φ = 712752624.

The previous prime is 2138257873. The next prime is 2138257931. The reversal of 2138257878 is 8787528312.

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

2138257878 is an admirable number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 2138257878.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2138257873) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 178188151 + ... + 178188162.

It is an arithmetic number, because the mean of its divisors is an integer number (534564471).

Almost surely, 2^2138257878 is an apocalyptic number.

2138257878 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

2138257878 is a wasteful number, since it uses less digits than its factorization.

2138257878 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 356376318.

The product of its digits is 1505280, while the sum is 51.

The square root of 2138257878 is about 46241.3005656199. The cubic root of 2138257878 is about 1288.3089590185.

The spelling of 2138257878 in words is "two billion, one hundred thirty-eight million, two hundred fifty-seven thousand, eight hundred seventy-eight".