2139978 has 8 divisors (see below), whose sum is σ = 4279968. Its totient is φ = 713324.

The previous prime is 2139967. The next prime is 2139979. The reversal of 2139978 is 8799312.

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

2139978 is an admirable number.

It is an Ulam number.

It is not an unprimeable number, because it can be changed into a prime (2139979) 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, 178326 + ... + 178337.

It is an arithmetic number, because the mean of its divisors is an integer number (534996).

2^2139978 is an apocalyptic number.

2139978 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.

2139978 is a wasteful number, since it uses less digits than its factorization.

2139978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 356668.

The product of its digits is 27216, while the sum is 39.

The square root of 2139978 is about 1462.8663643683. The cubic root of 2139978 is about 128.8654326562.

The spelling of 2139978 in words is "two million, one hundred thirty-nine thousand, nine hundred seventy-eight".