661167386884 has 9 divisors (see below), whose sum is σ = 1157045772981. Its totient is φ = 330582880320.

The previous prime is 661167386839. The next prime is 661167386911. The reversal of 661167386884 is 488683761166.

The square root of 661167386884 is 813122.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 72080436484 + 589086950400 = 268478^2 + 767520^2 .

It is a Duffinian number.

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 2 ways as a sum of consecutive naturals, for example, 1422964 + ... + 1829524.

Almost surely, 2^661167386884 is an apocalyptic number.

661167386884 is the 813122-nd square number.

It is an amenable number.

661167386884 is a deficient number, since it is larger than the sum of its proper divisors (495878386097).

661167386884 is an frugal number, since it uses more digits than its factorization.

661167386884 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 813126 (or 406563 counting only the distinct ones).

The product of its digits is 55738368, while the sum is 64.

Multiplying 661167386884 by its sum of digits (64), we get a square (42314712760576 = 6504976²).

The spelling of 661167386884 in words is "six hundred sixty-one billion, one hundred sixty-seven million, three hundred eighty-six thousand, eight hundred eighty-four".