6928639 has 4 divisors (see below), whose sum is σ = 7336224. Its totient is φ = 6521056.

The previous prime is 6928619. The next prime is 6928643. The reversal of 6928639 is 9368296.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 6928639 - 2⁷ = 6928511 is a prime.

It is a Duffinian number.

6928639 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 6928595 and 6928604.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6928609) 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, 203767 + ... + 203800.

It is an arithmetic number, because the mean of its divisors is an integer number (1834056).

Almost surely, 2^6928639 is an apocalyptic number.

6928639 is a deficient number, since it is larger than the sum of its proper divisors (407585).

6928639 is a wasteful number, since it uses less digits than its factorization.

6928639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 407584.

The product of its digits is 139968, while the sum is 43.

The square root of 6928639 is about 2632.2308029502. The cubic root of 6928639 is about 190.6408554043.

Adding to 6928639 its product of digits (139968), we get a palindrome (7068607).

The spelling of 6928639 in words is "six million, nine hundred twenty-eight thousand, six hundred thirty-nine".