673431821 has 2 divisors, whose sum is σ = 673431822. Its totient is φ = 673431820.

The previous prime is 673431809. The next prime is 673431827. The reversal of 673431821 is 128134376.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 612810025 + 60621796 = 24755^2 + 7786^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-673431821 is a prime.

It is a super-4 number, since 4×673431821⁴ (a number of 36 digits) contains 4444 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is equal to p_34947314 and since 673431821 and 34947314 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (673431827) 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, 336715910 + 336715911.

It is an arithmetic number, because the mean of its divisors is an integer number (336715911).

Almost surely, 2^673431821 is an apocalyptic number.

It is an amenable number.

673431821 is a deficient number, since it is larger than the sum of its proper divisors (1).

673431821 is an equidigital number, since it uses as much as digits as its factorization.

673431821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 24192, while the sum is 35.

The square root of 673431821 is about 25950.5649456809. The cubic root of 673431821 is about 876.5254786836.

The spelling of 673431821 in words is "six hundred seventy-three million, four hundred thirty-one thousand, eight hundred twenty-one".