671647100209 has 2 divisors, whose sum is σ = 671647100210. Its totient is φ = 671647100208.

The previous prime is 671647100183. The next prime is 671647100237. The reversal of 671647100209 is 902001746176.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 417772200609 + 253874899600 = 646353^2 + 503860^2 .

It is a cyclic number.

It is not a de Polignac number, because 671647100209 - 2⁵ = 671647100177 is a prime.

It is a super-2 number, since 2×671647100209² (a number of 24 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (671647100249) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 335823550104 + 335823550105.

It is an arithmetic number, because the mean of its divisors is an integer number (335823550105).

Almost surely, 2^671647100209 is an apocalyptic number.

It is an amenable number.

671647100209 is a deficient number, since it is larger than the sum of its proper divisors (1).

671647100209 is an equidigital number, since it uses as much as digits as its factorization.

671647100209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 127008, while the sum is 43.

The spelling of 671647100209 in words is "six hundred seventy-one billion, six hundred forty-seven million, one hundred thousand, two hundred nine".