661668863 has 16 divisors (see below), whose sum is σ = 705815040. Its totient is φ = 618516000.

The previous prime is 661668827. The next prime is 661668869. The reversal of 661668863 is 368866166.

It is a cyclic number.

It is not a de Polignac number, because 661668863 - 2⁸ = 661668607 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661668869) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 478433 + ... + 479813.

It is an arithmetic number, because the mean of its divisors is an integer number (44113440).

Almost surely, 2^661668863 is an apocalyptic number.

661668863 is a deficient number, since it is larger than the sum of its proper divisors (44146177).

661668863 is a wasteful number, since it uses less digits than its factorization.

661668863 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1718.

The product of its digits is 1492992, while the sum is 50.

The square root of 661668863 is about 25722.9248531344. The cubic root of 661668863 is about 871.3919949954.

The spelling of 661668863 in words is "six hundred sixty-one million, six hundred sixty-eight thousand, eight hundred sixty-three".