672807721 has 2 divisors, whose sum is σ = 672807722. Its totient is φ = 672807720.

The previous prime is 672807703. The next prime is 672807731. The reversal of 672807721 is 127708276.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 668946496 + 3861225 = 25864^2 + 1965^2 .

It is a cyclic number.

It is not a de Polignac number, because 672807721 - 2¹¹ = 672805673 is a prime.

It is not a weakly prime, because it can be changed into another prime (672807701) 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, 336403860 + 336403861.

It is an arithmetic number, because the mean of its divisors is an integer number (336403861).

Almost surely, 2^672807721 is an apocalyptic number.

It is an amenable number.

672807721 is a deficient number, since it is larger than the sum of its proper divisors (1).

672807721 is an equidigital number, since it uses as much as digits as its factorization.

672807721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 65856, while the sum is 40.

The square root of 672807721 is about 25938.5373720262. The cubic root of 672807721 is about 876.2546229414.

The spelling of 672807721 in words is "six hundred seventy-two million, eight hundred seven thousand, seven hundred twenty-one".