673427781 has 24 divisors (see below), whose sum is σ = 1051497720. Its totient is φ = 412857216.

The previous prime is 673427767. The next prime is 673427803. The reversal of 673427781 is 187724376.

It can be written as a sum of positive squares in 4 ways, for example, as 46376100 + 627051681 = 6810^2 + 25041^2 .

It is not a de Polignac number, because 673427781 - 2¹⁰ = 673426757 is a prime.

It is a super-2 number, since 2×673427781² = 907009952445167922, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (673427731) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 20775 + ... + 42171.

It is an arithmetic number, because the mean of its divisors is an integer number (43812405).

Almost surely, 2^673427781 is an apocalyptic number.

It is an amenable number.

673427781 is a deficient number, since it is larger than the sum of its proper divisors (378069939).

673427781 is a wasteful number, since it uses less digits than its factorization.

673427781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21685 (or 21682 counting only the distinct ones).

The product of its digits is 395136, while the sum is 45.

The square root of 673427781 is about 25950.4871052549. The cubic root of 673427781 is about 876.5237258855.

The spelling of 673427781 in words is "six hundred seventy-three million, four hundred twenty-seven thousand, seven hundred eighty-one".