66121801 has 2 divisors, whose sum is σ = 66121802. Its totient is φ = 66121800.

The previous prime is 66121787. The next prime is 66121841. The reversal of 66121801 is 10812166.

66121801 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 42889401 + 23232400 = 6549^2 + 4820^2 .

It is a cyclic number.

It is not a de Polignac number, because 66121801 - 2¹⁵ = 66089033 is a prime.

It is not a weakly prime, because it can be changed into another prime (66121841) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33060900 + 33060901.

It is an arithmetic number, because the mean of its divisors is an integer number (33060901).

Almost surely, 2^66121801 is an apocalyptic number.

It is an amenable number.

66121801 is a deficient number, since it is larger than the sum of its proper divisors (1).

66121801 is an equidigital number, since it uses as much as digits as its factorization.

66121801 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 576, while the sum is 25.

The square root of 66121801 is about 8131.5312826060. The cubic root of 66121801 is about 404.3724488244.

Adding to 66121801 its reverse (10812166), we get a palindrome (76933967).

The spelling of 66121801 in words is "sixty-six million, one hundred twenty-one thousand, eight hundred one".