66655651 has 4 divisors (see below), whose sum is σ = 66723904. Its totient is φ = 66587400.

The previous prime is 66655613. The next prime is 66655661. The reversal of 66655651 is 15655666.

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 66655651 - 2¹⁵ = 66622883 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66655661) 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, 32640 + ... + 34621.

It is an arithmetic number, because the mean of its divisors is an integer number (16680976).

Almost surely, 2^66655651 is an apocalyptic number.

66655651 is a deficient number, since it is larger than the sum of its proper divisors (68253).

66655651 is an equidigital number, since it uses as much as digits as its factorization.

66655651 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 68252.

The product of its digits is 162000, while the sum is 40.

The square root of 66655651 is about 8164.2912123466. The cubic root of 66655651 is about 405.4577986381.

The spelling of 66655651 in words is "sixty-six million, six hundred fifty-five thousand, six hundred fifty-one".