66552521 has 4 divisors (see below), whose sum is σ = 76060032. Its totient is φ = 57045012.

The previous prime is 66552511. The next prime is 66552527. The reversal of 66552521 is 12525566.

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 66552521 - 2¹⁰ = 66551497 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66552527) 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, 4753745 + ... + 4753758.

It is an arithmetic number, because the mean of its divisors is an integer number (19015008).

Almost surely, 2^66552521 is an apocalyptic number.

It is an amenable number.

66552521 is a deficient number, since it is larger than the sum of its proper divisors (9507511).

66552521 is an equidigital number, since it uses as much as digits as its factorization.

66552521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9507510.

The product of its digits is 18000, while the sum is 32.

The square root of 66552521 is about 8157.9728486923. The cubic root of 66552521 is about 405.2485818345.

The spelling of 66552521 in words is "sixty-six million, five hundred fifty-two thousand, five hundred twenty-one".