671962021 has 2 divisors, whose sum is σ = 671962022. Its totient is φ = 671962020.

The previous prime is 671962019. The next prime is 671962061. The reversal of 671962021 is 120269176.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 429069796 + 242892225 = 20714^2 + 15585^2 .

It is a cyclic number.

It is not a de Polignac number, because 671962021 - 2¹ = 671962019 is a prime.

Together with 671962019, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (671962061) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 335981010 + 335981011.

It is an arithmetic number, because the mean of its divisors is an integer number (335981011).

Almost surely, 2^671962021 is an apocalyptic number.

It is an amenable number.

671962021 is a deficient number, since it is larger than the sum of its proper divisors (1).

671962021 is an equidigital number, since it uses as much as digits as its factorization.

671962021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 9072, while the sum is 34.

The square root of 671962021 is about 25922.2302474151. The cubic root of 671962021 is about 875.8873266987.

The spelling of 671962021 in words is "six hundred seventy-one million, nine hundred sixty-two thousand, twenty-one".