66630521 has 4 divisors (see below), whose sum is σ = 68180112. Its totient is φ = 65080932.

The previous prime is 66630503. The next prime is 66630523. The reversal of 66630521 is 12503666.

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 66630521 - 2¹⁴ = 66614137 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66630523) 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, 774731 + ... + 774816.

It is an arithmetic number, because the mean of its divisors is an integer number (17045028).

Almost surely, 2^66630521 is an apocalyptic number.

It is an amenable number.

66630521 is a deficient number, since it is larger than the sum of its proper divisors (1549591).

66630521 is a wasteful number, since it uses less digits than its factorization.

66630521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1549590.

The product of its (nonzero) digits is 6480, while the sum is 29.

The square root of 66630521 is about 8162.7520481759. The cubic root of 66630521 is about 405.4068380415.

The spelling of 66630521 in words is "sixty-six million, six hundred thirty thousand, five hundred twenty-one".