66316921 has 4 divisors (see below), whose sum is σ = 72345744. Its totient is φ = 60288100.

The previous prime is 66316891. The next prime is 66316927. The reversal of 66316921 is 12961366.

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 a de Polignac number, because none of the positive numbers 2^k-66316921 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66316927) 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, 3014395 + ... + 3014416.

It is an arithmetic number, because the mean of its divisors is an integer number (18086436).

Almost surely, 2^66316921 is an apocalyptic number.

It is an amenable number.

66316921 is a deficient number, since it is larger than the sum of its proper divisors (6028823).

66316921 is a wasteful number, since it uses less digits than its factorization.

66316921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6028822.

The product of its digits is 11664, while the sum is 34.

The square root of 66316921 is about 8143.5201847850. The cubic root of 66316921 is about 404.7698148355.

The spelling of 66316921 in words is "sixty-six million, three hundred sixteen thousand, nine hundred twenty-one".