66819621101 has 4 divisors (see below), whose sum is σ = 66937055100. Its totient is φ = 66702187104.

The previous prime is 66819621023. The next prime is 66819621103. The reversal of 66819621101 is 10112691866.

66819621101 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 20894702500 + 45924918601 = 144550^2 + 214301^2 .

It is a cyclic number.

It is not a de Polignac number, because 66819621101 - 2²⁶ = 66752512237 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66819621103) 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, 58716146 + ... + 58717283.

It is an arithmetic number, because the mean of its divisors is an integer number (16734263775).

Almost surely, 2^66819621101 is an apocalyptic number.

It is an amenable number.

66819621101 is a deficient number, since it is larger than the sum of its proper divisors (117433999).

66819621101 is a wasteful number, since it uses less digits than its factorization.

66819621101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 117433998.

The product of its (nonzero) digits is 31104, while the sum is 41.

The spelling of 66819621101 in words is "sixty-six billion, eight hundred nineteen million, six hundred twenty-one thousand, one hundred one".