66349921 has 4 divisors (see below), whose sum is σ = 72381744. Its totient is φ = 60318100.

The previous prime is 66349909. The next prime is 66349937. The reversal of 66349921 is 12994366.

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 66349921 - 2¹¹ = 66347873 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66349961) 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, 3015895 + ... + 3015916.

It is an arithmetic number, because the mean of its divisors is an integer number (18095436).

Almost surely, 2^66349921 is an apocalyptic number.

It is an amenable number.

66349921 is a deficient number, since it is larger than the sum of its proper divisors (6031823).

66349921 is a wasteful number, since it uses less digits than its factorization.

66349921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6031822.

The product of its digits is 69984, while the sum is 40.

The square root of 66349921 is about 8145.5460835969. The cubic root of 66349921 is about 404.8369429465.

The spelling of 66349921 in words is "sixty-six million, three hundred forty-nine thousand, nine hundred twenty-one".