66516451 has 4 divisors (see below), whose sum is σ = 66537304. Its totient is φ = 66495600.

The previous prime is 66516419. The next prime is 66516469. The reversal of 66516451 is 15461566.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 66516451 - 2⁵ = 66516419 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66516481) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4530 + ... + 12391.

It is an arithmetic number, because the mean of its divisors is an integer number (16634326).

Almost surely, 2^66516451 is an apocalyptic number.

66516451 is a deficient number, since it is larger than the sum of its proper divisors (20853).

66516451 is a wasteful number, since it uses less digits than its factorization.

66516451 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20852.

The product of its digits is 21600, while the sum is 34.

The square root of 66516451 is about 8155.7618283027. The cubic root of 66516451 is about 405.1753566700.

The spelling of 66516451 in words is "sixty-six million, five hundred sixteen thousand, four hundred fifty-one".