66266521 has 4 divisors (see below), whose sum is σ = 66558672. Its totient is φ = 65974372.

The previous prime is 66266513. The next prime is 66266533. The reversal of 66266521 is 12566266.

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 not a de Polignac number, because 66266521 - 2³ = 66266513 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66266581) 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, 145735 + ... + 146188.

It is an arithmetic number, because the mean of its divisors is an integer number (16639668).

Almost surely, 2^66266521 is an apocalyptic number.

It is an amenable number.

66266521 is a deficient number, since it is larger than the sum of its proper divisors (292151).

66266521 is a wasteful number, since it uses less digits than its factorization.

66266521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 292150.

The product of its digits is 25920, while the sum is 34.

The square root of 66266521 is about 8140.4251117494. The cubic root of 66266521 is about 404.6672489113.

The spelling of 66266521 in words is "sixty-six million, two hundred sixty-six thousand, five hundred twenty-one".