66265555021 has 2 divisors, whose sum is σ = 66265555022. Its totient is φ = 66265555020.

The previous prime is 66265555003. The next prime is 66265555049. The reversal of 66265555021 is 12055556266.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 37253246121 + 29012308900 = 193011^2 + 170330^2 .

It is a cyclic number.

It is not a de Polignac number, because 66265555021 - 2⁵ = 66265554989 is a prime.

It is a super-2 number, since 2×66265555021² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66265555721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33132777510 + 33132777511.

It is an arithmetic number, because the mean of its divisors is an integer number (33132777511).

Almost surely, 2^66265555021 is an apocalyptic number.

It is an amenable number.

66265555021 is a deficient number, since it is larger than the sum of its proper divisors (1).

66265555021 is an equidigital number, since it uses as much as digits as its factorization.

66265555021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 540000, while the sum is 43.

The spelling of 66265555021 in words is "sixty-six billion, two hundred sixty-five million, five hundred fifty-five thousand, twenty-one".