66647121 has 4 divisors (see below), whose sum is σ = 88862832. Its totient is φ = 44431412.

The previous prime is 66647083. The next prime is 66647137. The reversal of 66647121 is 12174666.

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-66647121 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (66647821) 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, 11107851 + ... + 11107856.

It is an arithmetic number, because the mean of its divisors is an integer number (22215708).

Almost surely, 2^66647121 is an apocalyptic number.

It is an amenable number.

66647121 is a deficient number, since it is larger than the sum of its proper divisors (22215711).

66647121 is a wasteful number, since it uses less digits than its factorization.

66647121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22215710.

The product of its digits is 12096, while the sum is 33.

The square root of 66647121 is about 8163.7687987841. The cubic root of 66647121 is about 405.4405022673.

The spelling of 66647121 in words is "sixty-six million, six hundred forty-seven thousand, one hundred twenty-one".