66864621811 has 4 divisors (see below), whose sum is σ = 72008054272. Its totient is φ = 61721189352.

The previous prime is 66864621781. The next prime is 66864621823. The reversal of 66864621811 is 11812646866.

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 66864621811 - 2¹³ = 66864613619 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66864621841) 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, 2571716211 + ... + 2571716236.

It is an arithmetic number, because the mean of its divisors is an integer number (18002013568).

Almost surely, 2^66864621811 is an apocalyptic number.

66864621811 is a deficient number, since it is larger than the sum of its proper divisors (5143432461).

66864621811 is a wasteful number, since it uses less digits than its factorization.

66864621811 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5143432460.

The product of its digits is 663552, while the sum is 49.

The spelling of 66864621811 in words is "sixty-six billion, eight hundred sixty-four million, six hundred twenty-one thousand, eight hundred eleven".