6691669 has 4 divisors (see below), whose sum is σ = 6696844. Its totient is φ = 6686496.

The previous prime is 6691661. The next prime is 6691687. The reversal of 6691669 is 9661966.

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.

It can be written as a sum of positive squares in 2 ways, for example, as 5116644 + 1575025 = 2262^2 + 1255^2 .

It is a cyclic number.

It is not a de Polignac number, because 6691669 - 2³ = 6691661 is a prime.

It is a super-2 number, since 2×6691669² = 89556868011122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6691661) 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, 1249 + ... + 3865.

It is an arithmetic number, because the mean of its divisors is an integer number (1674211).

Almost surely, 2^6691669 is an apocalyptic number.

It is an amenable number.

6691669 is a deficient number, since it is larger than the sum of its proper divisors (5175).

6691669 is a wasteful number, since it uses less digits than its factorization.

6691669 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5174.

The product of its digits is 104976, while the sum is 43.

The square root of 6691669 is about 2586.8260474953. The cubic root of 6691669 is about 188.4421932236.

The spelling of 6691669 in words is "six million, six hundred ninety-one thousand, six hundred sixty-nine".