66055221216557 has 2 divisors, whose sum is σ = 66055221216558. Its totient is φ = 66055221216556.

The previous prime is 66055221216547. The next prime is 66055221216581. The reversal of 66055221216557 is 75561212255066.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 54455706706921 + 11599514509636 = 7379411^2 + 3405806^2 .

It is a cyclic number.

It is not a de Polignac number, because 66055221216557 - 2⁸ = 66055221216301 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 66055221216499 and 66055221216508.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66055221216547) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33027610608278 + 33027610608279.

It is an arithmetic number, because the mean of its divisors is an integer number (33027610608279).

Almost surely, 2^{66055221216557} is an apocalyptic number.

It is an amenable number.

66055221216557 is a deficient number, since it is larger than the sum of its proper divisors (1).

66055221216557 is an equidigital number, since it uses as much as digits as its factorization.

66055221216557 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7560000, while the sum is 53.

The spelling of 66055221216557 in words is "sixty-six trillion, fifty-five billion, two hundred twenty-one million, two hundred sixteen thousand, five hundred fifty-seven".