66423421 has 4 divisors (see below), whose sum is σ = 68566144. Its totient is φ = 64280700.

The previous prime is 66423397. The next prime is 66423463. The reversal of 66423421 is 12432466.

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 66423421 - 2⁷ = 66423293 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 66423421.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66423481) 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, 1071315 + ... + 1071376.

It is an arithmetic number, because the mean of its divisors is an integer number (17141536).

Almost surely, 2^66423421 is an apocalyptic number.

It is an amenable number.

66423421 is a deficient number, since it is larger than the sum of its proper divisors (2142723).

66423421 is a wasteful number, since it uses less digits than its factorization.

66423421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2142722.

The product of its digits is 6912, while the sum is 28.

The square root of 66423421 is about 8150.0565028716. The cubic root of 66423421 is about 404.9863756022.

Adding to 66423421 its reverse (12432466), we get a palindrome (78855887).

The spelling of 66423421 in words is "sixty-six million, four hundred twenty-three thousand, four hundred twenty-one".