66553213 has 4 divisors (see below), whose sum is σ = 67808988. Its totient is φ = 65297440.

The previous prime is 66553189. The next prime is 66553217. The reversal of 66553213 is 31235566.

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 19740249 + 46812964 = 4443^2 + 6842^2 .

It is a cyclic number.

It is not a de Polignac number, because 66553213 - 2⁹ = 66552701 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66553217) 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, 627808 + ... + 627913.

It is an arithmetic number, because the mean of its divisors is an integer number (16952247).

Almost surely, 2^66553213 is an apocalyptic number.

It is an amenable number.

66553213 is a deficient number, since it is larger than the sum of its proper divisors (1255775).

66553213 is a wasteful number, since it uses less digits than its factorization.

66553213 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1255774.

The product of its digits is 16200, while the sum is 31.

The square root of 66553213 is about 8158.0152610791. The cubic root of 66553213 is about 405.2499863946.

Adding to 66553213 its reverse (31235566), we get a palindrome (97788779).

It can be divided in two parts, 66553 and 213, that added together give a palindrome (66766).

The spelling of 66553213 in words is "sixty-six million, five hundred fifty-three thousand, two hundred thirteen".