667210721266 has 16 divisors (see below), whose sum is σ = 1025327169720. Its totient is φ = 325436600320.

The previous prime is 667210721251. The next prime is 667210721291. The reversal of 667210721266 is 662127012766.

It can be written as a sum of positive squares in 4 ways, for example, as 596260408041 + 70950313225 = 772179^2 + 266365^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 448290 + ... + 1239106.

Almost surely, 2^667210721266 is an apocalyptic number.

667210721266 is a deficient number, since it is larger than the sum of its proper divisors (358116448454).

667210721266 is a wasteful number, since it uses less digits than its factorization.

667210721266 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 801149.

The product of its (nonzero) digits is 508032, while the sum is 46.

The spelling of 667210721266 in words is "six hundred sixty-seven billion, two hundred ten million, seven hundred twenty-one thousand, two hundred sixty-six".