6640969 has 4 divisors (see below), whose sum is σ = 6649344. Its totient is φ = 6632596.

The previous prime is 6640967. The next prime is 6640979. The reversal of 6640969 is 9690466.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 6640969 - 2¹ = 6640967 is a prime.

It is a super-2 number, since 2×6640969² = 88204938517922, which contains 22 as substring.

It is a Duffinian number.

6640969 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (6640967) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2857 + ... + 4630.

It is an arithmetic number, because the mean of its divisors is an integer number (1662336).

Almost surely, 2^6640969 is an apocalyptic number.

It is an amenable number.

6640969 is a deficient number, since it is larger than the sum of its proper divisors (8375).

6640969 is an equidigital number, since it uses as much as digits as its factorization.

6640969 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8374.

The product of its (nonzero) digits is 69984, while the sum is 40.

The square root of 6640969 is about 2577.0077609507. The cubic root of 6640969 is about 187.9650700912.

Subtracting from 6640969 its sum of digits (40), we obtain a square (6640929 = 2577²).

The spelling of 6640969 in words is "six million, six hundred forty thousand, nine hundred sixty-nine".