6657439 has 4 divisors (see below), whose sum is σ = 6701680. Its totient is φ = 6613200.

The previous prime is 6657437. The next prime is 6657449. The reversal of 6657439 is 9347566.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9347566 = 2 ⋅4673783.

It is a cyclic number.

It is not a de Polignac number, because 6657439 - 2¹ = 6657437 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6657437) 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, 21894 + ... + 22195.

It is an arithmetic number, because the mean of its divisors is an integer number (1675420).

Almost surely, 2^6657439 is an apocalyptic number.

6657439 is a deficient number, since it is larger than the sum of its proper divisors (44241).

6657439 is a wasteful number, since it uses less digits than its factorization.

6657439 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44240.

The product of its digits is 136080, while the sum is 40.

The square root of 6657439 is about 2580.2013487323. The cubic root of 6657439 is about 188.1203300129.

The spelling of 6657439 in words is "six million, six hundred fifty-seven thousand, four hundred thirty-nine".