673956781 has 4 divisors (see below), whose sum is σ = 697196700. Its totient is φ = 650716864.

The previous prime is 673956761. The next prime is 673956791. The reversal of 673956781 is 187659376.

673956781 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 162970756 + 510986025 = 12766^2 + 22605^2 .

It is a cyclic number.

It is not a de Polignac number, because 673956781 - 2¹⁹ = 673432493 is a prime.

It is a super-3 number, since 3×673956781³ (a number of 27 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (673956761) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11619916 + ... + 11619973.

It is an arithmetic number, because the mean of its divisors is an integer number (174299175).

Almost surely, 2^673956781 is an apocalyptic number.

It is an amenable number.

673956781 is a deficient number, since it is larger than the sum of its proper divisors (23239919).

673956781 is a wasteful number, since it uses less digits than its factorization.

673956781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23239918.

The product of its digits is 1905120, while the sum is 52.

The square root of 673956781 is about 25960.6775913111. The cubic root of 673956781 is about 876.7531786963.

The spelling of 673956781 in words is "six hundred seventy-three million, nine hundred fifty-six thousand, seven hundred eighty-one".