6906639 has 8 divisors (see below), whose sum is σ = 9234432. Its totient is φ = 4591640.

The previous prime is 6906637. The next prime is 6906649. The reversal of 6906639 is 9366096.

6906639 is digitally balanced in base 3 and base 4, because in such bases it contains all the possibile digits an equal number of times.

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

It is a cyclic number.

It is not a de Polignac number, because 6906639 - 2¹ = 6906637 is a prime.

6906639 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 6906597 and 6906606.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6906631) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1857 + ... + 4154.

It is an arithmetic number, because the mean of its divisors is an integer number (1154304).

Almost surely, 2^6906639 is an apocalyptic number.

6906639 is a deficient number, since it is larger than the sum of its proper divisors (2327793).

6906639 is a wasteful number, since it uses less digits than its factorization.

6906639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6397.

The product of its (nonzero) digits is 52488, while the sum is 39.

The square root of 6906639 is about 2628.0485155339. The cubic root of 6906639 is about 190.4388654830.

The spelling of 6906639 in words is "six million, nine hundred six thousand, six hundred thirty-nine".