817669661 has 4 divisors (see below), whose sum is σ = 817753632. Its totient is φ = 817585692.

The previous prime is 817669649. The next prime is 817669667. The reversal of 817669661 is 166966718.

817669661 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, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 817669661 - 2⁶ = 817669597 is a prime.

It is a super-3 number, since 3×817669661³ (a number of 28 digits) contains 333 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 (817669667) 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, 25121 + ... + 47606.

It is an arithmetic number, because the mean of its divisors is an integer number (204438408).

Almost surely, 2^817669661 is an apocalyptic number.

It is an amenable number.

817669661 is a deficient number, since it is larger than the sum of its proper divisors (83971).

817669661 is a wasteful number, since it uses less digits than its factorization.

817669661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 83970.

The product of its digits is 653184, while the sum is 50.

The square root of 817669661 is about 28594.9236928515. The cubic root of 817669661 is about 935.1026648113.

The spelling of 817669661 in words is "eight hundred seventeen million, six hundred sixty-nine thousand, six hundred sixty-one".