673021981 has 4 divisors (see below), whose sum is σ = 673076992. Its totient is φ = 672966972.

The previous prime is 673021963. The next prime is 673022003. The reversal of 673021981 is 189120376.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 673021981 - 2¹¹ = 673019933 is a prime.

It is a super-2 number, since 2×673021981² = 905917173818328722, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 673021981.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (673021961) 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 in 3 ways as a sum of consecutive naturals, for example, 46 + ... + 36688.

It is an arithmetic number, because the mean of its divisors is an integer number (168269248).

Almost surely, 2^673021981 is an apocalyptic number.

It is an amenable number.

673021981 is a deficient number, since it is larger than the sum of its proper divisors (55011).

673021981 is a wasteful number, since it uses less digits than its factorization.

673021981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55010.

The product of its (nonzero) digits is 18144, while the sum is 37.

The square root of 673021981 is about 25942.6671913279. The cubic root of 673021981 is about 876.3476293995.

The spelling of 673021981 in words is "six hundred seventy-three million, twenty-one thousand, nine hundred eighty-one".