6939921 has 16 divisors (see below), whose sum is σ = 9838400. Its totient is φ = 4339008.

The previous prime is 6939901. The next prime is 6939923. The reversal of 6939921 is 1299396.

It is a happy number.

It is not a de Polignac number, because 6939921 - 2¹⁴ = 6923537 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 6939921.

It is not an unprimeable number, because it can be changed into a prime (6939923) 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 15 ways as a sum of consecutive naturals, for example, 5655 + ... + 6771.

It is an arithmetic number, because the mean of its divisors is an integer number (614900).

Almost surely, 2^6939921 is an apocalyptic number.

It is an amenable number.

6939921 is a deficient number, since it is larger than the sum of its proper divisors (2898479).

6939921 is a wasteful number, since it uses less digits than its factorization.

6939921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1248.

The product of its digits is 26244, while the sum is 39.

The square root of 6939921 is about 2634.3729804263. The cubic root of 6939921 is about 190.7442736844.

The spelling of 6939921 in words is "six million, nine hundred thirty-nine thousand, nine hundred twenty-one".