66693213 has 10 divisors (see below), whose sum is σ = 99628254. Its totient is φ = 44462088.

The previous prime is 66693199. The next prime is 66693217. The reversal of 66693213 is 31239666.

It can be written as a sum of positive squares in only one way, i.e., 49028004 + 17665209 = 7002^2 + 4203^2 .

It is not a de Polignac number, because 66693213 - 2⁹ = 66692701 is a prime.

It is a zygodrome in base 3.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66693217) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 411606 + ... + 411767.

Almost surely, 2^66693213 is an apocalyptic number.

It is an amenable number.

66693213 is a deficient number, since it is larger than the sum of its proper divisors (32935041).

66693213 is an equidigital number, since it uses as much as digits as its factorization.

66693213 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 823385 (or 823376 counting only the distinct ones).

The product of its digits is 34992, while the sum is 36.

The square root of 66693213 is about 8166.5912717608. The cubic root of 66693213 is about 405.5339459500.

The spelling of 66693213 in words is "sixty-six million, six hundred ninety-three thousand, two hundred thirteen".