66642223 has 4 divisors (see below), whose sum is σ = 66818440. Its totient is φ = 66466008.

The previous prime is 66642197. The next prime is 66642259. The reversal of 66642223 is 32224666.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 32224666 = 2 ⋅16112333.

It is a cyclic number.

It is not a de Polignac number, because 66642223 - 2⁹ = 66641711 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 (66642263) 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, 87540 + ... + 88297.

It is an arithmetic number, because the mean of its divisors is an integer number (16704610).

Almost surely, 2^66642223 is an apocalyptic number.

66642223 is a deficient number, since it is larger than the sum of its proper divisors (176217).

66642223 is a wasteful number, since it uses less digits than its factorization.

66642223 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 176216.

The product of its digits is 20736, while the sum is 31.

The square root of 66642223 is about 8163.4688092746. The cubic root of 66642223 is about 405.4305698741.

Adding to 66642223 its reverse (32224666), we get a palindrome (98866889).

The spelling of 66642223 in words is "sixty-six million, six hundred forty-two thousand, two hundred twenty-three".