665628869 has 4 divisors (see below), whose sum is σ = 687100800. Its totient is φ = 644156940.

The previous prime is 665628839. The next prime is 665628877. The reversal of 665628869 is 968826566.

665628869 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 665628869 - 2²⁸ = 397193413 is a prime.

It is a super-2 number, since 2×665628869² = 886123582492438322, 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 (665628839) 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, 10735919 + ... + 10735980.

It is an arithmetic number, because the mean of its divisors is an integer number (171775200).

Almost surely, 2^665628869 is an apocalyptic number.

It is an amenable number.

665628869 is a deficient number, since it is larger than the sum of its proper divisors (21471931).

665628869 is a wasteful number, since it uses less digits than its factorization.

665628869 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21471930.

The product of its digits is 7464960, while the sum is 56.

The square root of 665628869 is about 25799.7842820439. The cubic root of 665628869 is about 873.1269294319.

The spelling of 665628869 in words is "six hundred sixty-five million, six hundred twenty-eight thousand, eight hundred sixty-nine".