66645213554401 has 4 divisors (see below), whose sum is σ = 67902670413972. Its totient is φ = 65387756694832.

The previous prime is 66645213554377. The next prime is 66645213554419. The reversal of 66645213554401 is 10445531254666.

66645213554401 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It can be written as a sum of positive squares in 2 ways, for example, as 57261774256801 + 9383439297600 = 7567151^2 + 3063240^2 .

It is a cyclic number.

It is not a de Polignac number, because 66645213554401 - 2⁷ = 66645213554273 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66645211554401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 628728429706 + ... + 628728429811.

It is an arithmetic number, because the mean of its divisors is an integer number (16975667603493).

Almost surely, 2^{66645213554401} is an apocalyptic number.

It is an amenable number.

66645213554401 is a deficient number, since it is larger than the sum of its proper divisors (1257456859571).

66645213554401 is a wasteful number, since it uses less digits than its factorization.

66645213554401 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1257456859570.

The product of its (nonzero) digits is 10368000, while the sum is 52.

The spelling of 66645213554401 in words is "sixty-six trillion, six hundred forty-five billion, two hundred thirteen million, five hundred fifty-four thousand, four hundred one".