66820101 has 4 divisors (see below), whose sum is σ = 89093472. Its totient is φ = 44546732.

The previous prime is 66820079. The next prime is 66820111. The reversal of 66820101 is 10102866.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 66820101 - 2¹¹ = 66818053 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66820111) 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, 11136681 + ... + 11136686.

It is an arithmetic number, because the mean of its divisors is an integer number (22273368).

Almost surely, 2^66820101 is an apocalyptic number.

It is an amenable number.

66820101 is a deficient number, since it is larger than the sum of its proper divisors (22273371).

66820101 is a wasteful number, since it uses less digits than its factorization.

66820101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22273370.

The product of its (nonzero) digits is 576, while the sum is 24.

The square root of 66820101 is about 8174.3563049331. The cubic root of 66820101 is about 405.7909675661.

Adding to 66820101 its reverse (10102866), we get a palindrome (76922967).

The spelling of 66820101 in words is "sixty-six million, eight hundred twenty thousand, one hundred one".