674509721 has 2 divisors, whose sum is σ = 674509722. Its totient is φ = 674509720.

The previous prime is 674509673. The next prime is 674509723. The reversal of 674509721 is 127905476.

674509721 = 18364² + 18365².

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 337273225 + 337236496 = 18365^2 + 18364^2 .

It is a cyclic number.

It is not a de Polignac number, because 674509721 - 2⁶ = 674509657 is a prime.

It is a Sophie Germain prime.

Together with 674509723, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (674509723) 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, 337254860 + 337254861.

It is an arithmetic number, because the mean of its divisors is an integer number (337254861).

Almost surely, 2^674509721 is an apocalyptic number.

674509721 is the 18365-th centered square number.

It is an amenable number.

674509721 is a deficient number, since it is larger than the sum of its proper divisors (1).

674509721 is an equidigital number, since it uses as much as digits as its factorization.

674509721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 105840, while the sum is 41.

The square root of 674509721 is about 25971.3249758267. The cubic root of 674509721 is about 876.9928871346.

The spelling of 674509721 in words is "six hundred seventy-four million, five hundred nine thousand, seven hundred twenty-one".