66163121 has 2 divisors, whose sum is σ = 66163122. Its totient is φ = 66163120.

The previous prime is 66163117. The next prime is 66163151. The reversal of 66163121 is 12136166.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 64625521 + 1537600 = 8039^2 + 1240^2 .

It is a cyclic number.

It is not a de Polignac number, because 66163121 - 2² = 66163117 is a prime.

It is not a weakly prime, because it can be changed into another prime (66163151) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33081560 + 33081561.

It is an arithmetic number, because the mean of its divisors is an integer number (33081561).

Almost surely, 2^66163121 is an apocalyptic number.

It is an amenable number.

66163121 is a deficient number, since it is larger than the sum of its proper divisors (1).

66163121 is an equidigital number, since it uses as much as digits as its factorization.

66163121 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1296, while the sum is 26.

The square root of 66163121 is about 8134.0716126673. The cubic root of 66163121 is about 404.4566630577.

Adding to 66163121 its reverse (12136166), we get a palindrome (78299287).

The spelling of 66163121 in words is "sixty-six million, one hundred sixty-three thousand, one hundred twenty-one".