6649997 has 4 divisors (see below), whose sum is σ = 6655740. Its totient is φ = 6644256.

The previous prime is 6649919. The next prime is 6649999. The reversal of 6649997 is 7999466.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 7999466 = 2 ⋅3999733.

It can be written as a sum of positive squares in 2 ways, for example, as 5900041 + 749956 = 2429^2 + 866^2 .

It is a cyclic number.

It is not a de Polignac number, because 6649997 - 2¹⁸ = 6387853 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 (6649999) 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, 458 + ... + 3675.

It is an arithmetic number, because the mean of its divisors is an integer number (1663935).

Almost surely, 2^6649997 is an apocalyptic number.

It is an amenable number.

6649997 is a deficient number, since it is larger than the sum of its proper divisors (5743).

6649997 is a wasteful number, since it uses less digits than its factorization.

6649997 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5742.

The product of its digits is 734832, while the sum is 50.

The square root of 6649997 is about 2578.7588099704. The cubic root of 6649997 is about 188.0502072785.

The spelling of 6649997 in words is "six million, six hundred forty-nine thousand, nine hundred ninety-seven".