813820661 has 8 divisors (see below), whose sum is σ = 872156544. Its totient is φ = 757397520.

The previous prime is 813820627. The next prime is 813820669. The reversal of 813820661 is 166028318.

813820661 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-813820661 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (813820669) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 477305 + ... + 479006.

It is an arithmetic number, because the mean of its divisors is an integer number (109019568).

Almost surely, 2^813820661 is an apocalyptic number.

It is an amenable number.

813820661 is a deficient number, since it is larger than the sum of its proper divisors (58335883).

813820661 is a wasteful number, since it uses less digits than its factorization.

813820661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 956371.

The product of its (nonzero) digits is 13824, while the sum is 35.

The square root of 813820661 is about 28527.5421478963. The cubic root of 813820661 is about 933.6330931571.

Adding to 813820661 its reverse (166028318), we get a palindrome (979848979).

The spelling of 813820661 in words is "eight hundred thirteen million, eight hundred twenty thousand, six hundred sixty-one".