66451651 has 4 divisors (see below), whose sum is σ = 75944752. Its totient is φ = 56958552.

The previous prime is 66451633. The next prime is 66451687. The reversal of 66451651 is 15615466.

It is a happy number.

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

It is not a de Polignac number, because 66451651 - 2⁹ = 66451139 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66451951) 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, 4746540 + ... + 4746553.

It is an arithmetic number, because the mean of its divisors is an integer number (18986188).

Almost surely, 2^66451651 is an apocalyptic number.

66451651 is a deficient number, since it is larger than the sum of its proper divisors (9493101).

66451651 is an equidigital number, since it uses as much as digits as its factorization.

66451651 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9493100.

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

The square root of 66451651 is about 8151.7882087306. The cubic root of 66451651 is about 405.0437406398.

The spelling of 66451651 in words is "sixty-six million, four hundred fifty-one thousand, six hundred fifty-one".