669688891 has 8 divisors (see below), whose sum is σ = 674109968. Its totient is φ = 665280000.

The previous prime is 669688843. The next prime is 669688897. The reversal of 669688891 is 198886966.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 669688891 - 2¹³ = 669680699 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (669688897) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 124171 + ... + 129451.

It is an arithmetic number, because the mean of its divisors is an integer number (84263746).

Almost surely, 2^669688891 is an apocalyptic number.

669688891 is a deficient number, since it is larger than the sum of its proper divisors (4421077).

669688891 is a wasteful number, since it uses less digits than its factorization.

669688891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6093.

The product of its digits is 8957952, while the sum is 61.

The square root of 669688891 is about 25878.3479186752. The cubic root of 669688891 is about 874.8985530279.

The spelling of 669688891 in words is "six hundred sixty-nine million, six hundred eighty-eight thousand, eight hundred ninety-one".