66640223 has 8 divisors (see below), whose sum is σ = 74887008. Its totient is φ = 58839264.

The previous prime is 66640199. The next prime is 66640229. The reversal of 66640223 is 32204666.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 66640223 - 2⁶ = 66640159 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 (66640229) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 111140 + ... + 111737.

It is an arithmetic number, because the mean of its divisors is an integer number (9360876).

Almost surely, 2^66640223 is an apocalyptic number.

66640223 is a deficient number, since it is larger than the sum of its proper divisors (8246785).

66640223 is a wasteful number, since it uses less digits than its factorization.

66640223 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 222913.

The product of its (nonzero) digits is 10368, while the sum is 29.

The square root of 66640223 is about 8163.3463114093. The cubic root of 66640223 is about 405.4265140408.

Adding to 66640223 its reverse (32204666), we get a palindrome (98844889).

The spelling of 66640223 in words is "sixty-six million, six hundred forty thousand, two hundred twenty-three".