66677881 has 2 divisors, whose sum is σ = 66677882. Its totient is φ = 66677880.

The previous prime is 66677861. The next prime is 66677887. The reversal of 66677881 is 18877666.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 62267881 + 4410000 = 7891^2 + 2100^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66677881 is a prime.

It is a super-2 number, since 2×66677881² = 8891879629300322, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (66677887) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33338940 + 33338941.

It is an arithmetic number, because the mean of its divisors is an integer number (33338941).

Almost surely, 2^66677881 is an apocalyptic number.

It is an amenable number.

66677881 is a deficient number, since it is larger than the sum of its proper divisors (1).

66677881 is an equidigital number, since it uses as much as digits as its factorization.

66677881 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 677376, while the sum is 49.

The square root of 66677881 is about 8165.6525152617. The cubic root of 66677881 is about 405.5028677104.

The spelling of 66677881 in words is "sixty-six million, six hundred seventy-seven thousand, eight hundred eighty-one".