66124521 has 6 divisors (see below), whose sum is σ = 95513210. Its totient is φ = 44083008.

The previous prime is 66124493. The next prime is 66124529. The reversal of 66124521 is 12542166.

66124521 is a `hidden beast` number, since 6 + 612 + 45 + 2 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 51194025 + 14930496 = 7155^2 + 3864^2 .

It is not a de Polignac number, because 66124521 - 2⁵ = 66124489 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (66124529) 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 5 ways as a sum of consecutive naturals, for example, 3673576 + ... + 3673593.

Almost surely, 2^66124521 is an apocalyptic number.

It is an amenable number.

66124521 is a deficient number, since it is larger than the sum of its proper divisors (29388689).

66124521 is a wasteful number, since it uses less digits than its factorization.

66124521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7347175 (or 7347172 counting only the distinct ones).

The product of its digits is 2880, while the sum is 27.

The square root of 66124521 is about 8131.6985310573. The cubic root of 66124521 is about 404.3779935311.

Adding to 66124521 its reverse (12542166), we get a palindrome (78666687).

The spelling of 66124521 in words is "sixty-six million, one hundred twenty-four thousand, five hundred twenty-one".