856663961 has 8 divisors (see below), whose sum is σ = 864876960. Its totient is φ = 848462272.

The previous prime is 856663909. The next prime is 856663981. The reversal of 856663961 is 169366658.

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

It is a cyclic number.

It is not a de Polignac number, because 856663961 - 2⁶ = 856663897 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (856663901) 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 7 ways as a sum of consecutive naturals, for example, 276326 + ... + 279408.

It is an arithmetic number, because the mean of its divisors is an integer number (108109620).

Almost surely, 2^856663961 is an apocalyptic number.

It is an amenable number.

856663961 is a deficient number, since it is larger than the sum of its proper divisors (8212999).

856663961 is a wasteful number, since it uses less digits than its factorization.

856663961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5655.

The product of its digits is 1399680, while the sum is 50.

The square root of 856663961 is about 29268.8223370876. The cubic root of 856663961 is about 949.7373090857.

It can be divided in two parts, 8566 and 63961, that added together give a palindrome (72527).

The spelling of 856663961 in words is "eight hundred fifty-six million, six hundred sixty-three thousand, nine hundred sixty-one".