66420886309801 has 3 divisors (see below), whose sum is σ = 66420894459703. Its totient is φ = 66420878159900.

The previous prime is 66420886309747. The next prime is 66420886309861. The reversal of 66420886309801 is 10890368802466.

The square root of 66420886309801 is 8149901.

It is a perfect power (a square), and thus also a powerful number.

66420886309801 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, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 48498702738201 + 17922183571600 = 6964101^2 + 4233460^2 .

It is not a de Polignac number, because 66420886309801 - 2²¹ = 66420884212649 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 66420886309801.

It is not an unprimeable number, because it can be changed into a prime (66420886309861) 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 2 ways as a sum of consecutive naturals, for example, 4074951 + ... + 12224851.

Almost surely, 2^{66420886309801} is an apocalyptic number.

66420886309801 is the 8149901-st square number.

66420886309801 is the 4074951-st centered octagonal number.

It is an amenable number.

66420886309801 is a deficient number, since it is larger than the sum of its proper divisors (8149902).

66420886309801 is an frugal number, since it uses more digits than its factorization.

66420886309801 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16299802 (or 8149901 counting only the distinct ones).

The product of its (nonzero) digits is 23887872, while the sum is 61.

The spelling of 66420886309801 in words is "sixty-six trillion, four hundred twenty billion, eight hundred eighty-six million, three hundred nine thousand, eight hundred one".