667073021 has 4 divisors (see below), whose sum is σ = 681266112. Its totient is φ = 652879932.

The previous prime is 667072951. The next prime is 667073053. The reversal of 667073021 is 120370766.

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 an emirpimes, since its reverse is a distinct semiprime: 120370766 = 2 ⋅60185383.

It is a cyclic number.

It is not a de Polignac number, because 667073021 - 2¹⁰ = 667071997 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (667075021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7096475 + ... + 7096568.

It is an arithmetic number, because the mean of its divisors is an integer number (170316528).

Almost surely, 2^667073021 is an apocalyptic number.

It is an amenable number.

667073021 is a deficient number, since it is larger than the sum of its proper divisors (14193091).

667073021 is a wasteful number, since it uses less digits than its factorization.

667073021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14193090.

The product of its (nonzero) digits is 10584, while the sum is 32.

The square root of 667073021 is about 25827.7567938062. The cubic root of 667073021 is about 873.7579202899.

The spelling of 667073021 in words is "six hundred sixty-seven million, seventy-three thousand, twenty-one".