669181889 has 4 divisors (see below), whose sum is σ = 687267924. Its totient is φ = 651095856.

The previous prime is 669181871. The next prime is 669181907. The reversal of 669181889 is 988181966.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 988181966 = 2 ⋅494090983.

It is an interprime number because it is at equal distance from previous prime (669181871) and next prime (669181907).

It can be written as a sum of positive squares in 2 ways, for example, as 368332864 + 300849025 = 19192^2 + 17345^2 .

It is a cyclic number.

It is not a de Polignac number, because 669181889 - 2¹⁶ = 669116353 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (669187889) 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 3 ways as a sum of consecutive naturals, for example, 9042962 + ... + 9043035.

It is an arithmetic number, because the mean of its divisors is an integer number (171816981).

Almost surely, 2^669181889 is an apocalyptic number.

It is an amenable number.

669181889 is a deficient number, since it is larger than the sum of its proper divisors (18086035).

669181889 is a wasteful number, since it uses less digits than its factorization.

669181889 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18086034.

The product of its digits is 1492992, while the sum is 56.

The square root of 669181889 is about 25868.5501913037. The cubic root of 669181889 is about 874.6777105299.

The spelling of 669181889 in words is "six hundred sixty-nine million, one hundred eighty-one thousand, eight hundred eighty-nine".