863680661 has 4 divisors (see below), whose sum is σ = 863752032. Its totient is φ = 863609292.

The previous prime is 863680651. The next prime is 863680667. The reversal of 863680661 is 166086368.

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 a de Polignac number, because none of the positive numbers 2^k-863680661 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 (863680667) 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, 12521 + ... + 43406.

It is an arithmetic number, because the mean of its divisors is an integer number (215938008).

Almost surely, 2^863680661 is an apocalyptic number.

It is an amenable number.

863680661 is a deficient number, since it is larger than the sum of its proper divisors (71371).

863680661 is a wasteful number, since it uses less digits than its factorization.

863680661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 71370.

The product of its (nonzero) digits is 248832, while the sum is 44.

The square root of 863680661 is about 29388.4443446740. Note that the first 3 decimals coincide. The cubic root of 863680661 is about 952.3232743451.

The spelling of 863680661 in words is "eight hundred sixty-three million, six hundred eighty thousand, six hundred sixty-one".