671640653 has 2 divisors, whose sum is σ = 671640654. Its totient is φ = 671640652.

The previous prime is 671640647. The next prime is 671640679. The reversal of 671640653 is 356046176.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 499164964 + 172475689 = 22342^2 + 13133^2 .

It is a cyclic number.

It is not a de Polignac number, because 671640653 - 2¹² = 671636557 is a prime.

It is a super-2 number, since 2×671640653² = 902202333524532818, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (671640623) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 335820326 + 335820327.

It is an arithmetic number, because the mean of its divisors is an integer number (335820327).

Almost surely, 2^671640653 is an apocalyptic number.

It is an amenable number.

671640653 is a deficient number, since it is larger than the sum of its proper divisors (1).

671640653 is an equidigital number, since it uses as much as digits as its factorization.

671640653 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 90720, while the sum is 38.

The square root of 671640653 is about 25916.0308110636. The cubic root of 671640653 is about 875.7476724550.

The spelling of 671640653 in words is "six hundred seventy-one million, six hundred forty thousand, six hundred fifty-three".