667588677721 has 27 divisors (see below), whose sum is σ = 782772379263. Its totient is φ = 567693982800.

The previous prime is 667588677677. The next prime is 667588677733. The reversal of 667588677721 is 127776885766.

The square root of 667588677721 is 817061.

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., 42483393225 + 625105284496 = 206115^2 + 790636^2 .

It is not a de Polignac number, because 667588677721 - 2¹⁵ = 667588644953 is a prime.

It is not an unprimeable number, because it can be changed into a prime (667588672721) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 863633091 + ... + 863633863.

Almost surely, 2^667588677721 is an apocalyptic number.

667588677721 is the 817061-st square number.

667588677721 is the 408531-st centered octagonal number.

It is an amenable number.

667588677721 is a deficient number, since it is larger than the sum of its proper divisors (115183701542).

667588677721 is an frugal number, since it uses more digits than its factorization.

667588677721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1862 (or 931 counting only the distinct ones).

The product of its digits is 331914240, while the sum is 70.

The spelling of 667588677721 in words is "six hundred sixty-seven billion, five hundred eighty-eight million, six hundred seventy-seven thousand, seven hundred twenty-one".