66667788881 has 2 divisors, whose sum is σ = 66667788882. Its totient is φ = 66667788880.

The previous prime is 66667788851. The next prime is 66667788883. The reversal of 66667788881 is 18888776666.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 47674539025 + 18993249856 = 218345^2 + 137816^2 .

It is a cyclic number.

It is not a de Polignac number, because 66667788881 - 2¹⁴ = 66667772497 is a prime.

It is a super-2 number, since 2×66667788881² (a number of 22 digits) contains 22 as substring.

Together with 66667788883, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (66667788883) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33333894440 + 33333894441.

It is an arithmetic number, because the mean of its divisors is an integer number (33333894441).

Almost surely, 2^66667788881 is an apocalyptic number.

It is an amenable number.

66667788881 is a deficient number, since it is larger than the sum of its proper divisors (1).

66667788881 is an equidigital number, since it uses as much as digits as its factorization.

66667788881 is an evil number, because the sum of its binary digits is even.

The product of its digits is 260112384, while the sum is 71.

The spelling of 66667788881 in words is "sixty-six billion, six hundred sixty-seven million, seven hundred eighty-eight thousand, eight hundred eighty-one".