6666399 has 6 divisors (see below), whose sum is σ = 9629256. Its totient is φ = 4444260.

The previous prime is 6666391. The next prime is 6666437. The reversal of 6666399 is 9936666.

It is not a de Polignac number, because 6666399 - 2³ = 6666391 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6666391) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 370347 + ... + 370364.

It is an arithmetic number, because the mean of its divisors is an integer number (1604876).

Almost surely, 2^6666399 is an apocalyptic number.

6666399 is a deficient number, since it is larger than the sum of its proper divisors (2962857).

6666399 is a wasteful number, since it uses less digits than its factorization.

6666399 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 740717 (or 740714 counting only the distinct ones).

The product of its digits is 314928, while the sum is 45.

The square root of 6666399 is about 2581.9370635242. The cubic root of 6666399 is about 188.2046869027.

The spelling of 6666399 in words is "six million, six hundred sixty-six thousand, three hundred ninety-nine".