661668110664 has 32 divisors (see below), whose sum is σ = 1804549393440. Its totient is φ = 200505488000.

The previous prime is 661668110647. The next prime is 661668110711. The reversal of 661668110664 is 466011866166.

It is an unprimeable number.

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, 1253159037 + ... + 1253159564.

It is an arithmetic number, because the mean of its divisors is an integer number (56392168545).

Almost surely, 2^661668110664 is an apocalyptic number.

It is an amenable number.

661668110664 is an abundant number, since it is smaller than the sum of its proper divisors (1142881282776).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

661668110664 is a wasteful number, since it uses less digits than its factorization.

661668110664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2506318621 (or 2506318617 counting only the distinct ones).

The product of its (nonzero) digits is 1492992, while the sum is 51.

The spelling of 661668110664 in words is "six hundred sixty-one billion, six hundred sixty-eight million, one hundred ten thousand, six hundred sixty-four".