66157213 has 4 divisors (see below), whose sum is σ = 66177280. Its totient is φ = 66137148.

The previous prime is 66157211. The next prime is 66157229. The reversal of 66157213 is 31275166.

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.

It is a cyclic number.

It is not a de Polignac number, because 66157213 - 2¹ = 66157211 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 (66157211) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3795 + ... + 12112.

It is an arithmetic number, because the mean of its divisors is an integer number (16544320).

Almost surely, 2^66157213 is an apocalyptic number.

It is an amenable number.

66157213 is a deficient number, since it is larger than the sum of its proper divisors (20067).

66157213 is a wasteful number, since it uses less digits than its factorization.

66157213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20066.

The product of its digits is 7560, while the sum is 31.

The square root of 66157213 is about 8133.7084408036. The cubic root of 66157213 is about 404.4446241199. Note that the first 3 decimals are identical.

The spelling of 66157213 in words is "sixty-six million, one hundred fifty-seven thousand, two hundred thirteen".