671200021 has 2 divisors, whose sum is σ = 671200022. Its totient is φ = 671200020.

The previous prime is 671199959. The next prime is 671200027. The reversal of 671200021 is 120002176.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 542377521 + 128822500 = 23289^2 + 11350^2 .

It is a cyclic number.

It is not a de Polignac number, because 671200021 - 2⁹ = 671199509 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (671200027) 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, 335600010 + 335600011.

It is an arithmetic number, because the mean of its divisors is an integer number (335600011).

Almost surely, 2^671200021 is an apocalyptic number.

It is an amenable number.

671200021 is a deficient number, since it is larger than the sum of its proper divisors (1).

671200021 is an equidigital number, since it uses as much as digits as its factorization.

671200021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 168, while the sum is 19.

The square root of 671200021 is about 25907.5282688256. The cubic root of 671200021 is about 875.5561182045.

Adding to 671200021 its reverse (120002176), we get a palindrome (791202197).

The spelling of 671200021 in words is "six hundred seventy-one million, two hundred thousand, twenty-one".