669654891 has 16 divisors (see below), whose sum is σ = 996207520. Its totient is φ = 444579840.

The previous prime is 669654857. The next prime is 669654893. The reversal of 669654891 is 198456966.

It is a happy number.

669654891 is a `hidden beast` number, since 6 + 6 + 9 + 6 + 548 + 91 = 666.

It is not a de Polignac number, because 669654891 - 2¹⁷ = 669523819 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (669654893) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 44950 + ... + 57963.

It is an arithmetic number, because the mean of its divisors is an integer number (62262970).

Almost surely, 2^669654891 is an apocalyptic number.

669654891 is a deficient number, since it is larger than the sum of its proper divisors (326552629).

669654891 is a wasteful number, since it uses less digits than its factorization.

669654891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 103163 (or 103157 counting only the distinct ones).

The product of its digits is 2799360, while the sum is 54.

The square root of 669654891 is about 25877.6909905038. The cubic root of 669654891 is about 874.8837466232.

The spelling of 669654891 in words is "six hundred sixty-nine million, six hundred fifty-four thousand, eight hundred ninety-one".