66057881 has 2 divisors, whose sum is σ = 66057882. Its totient is φ = 66057880.

The previous prime is 66057877. The next prime is 66057883. The reversal of 66057881 is 18875066.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 44342281 + 21715600 = 6659^2 + 4660^2 .

It is a cyclic number.

It is not a de Polignac number, because 66057881 - 2² = 66057877 is a prime.

It is a super-2 number, since 2×66057881² = 8727287284420322, which contains 22 as substring.

Together with 66057883, 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 (66057883) 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, 33028940 + 33028941.

It is an arithmetic number, because the mean of its divisors is an integer number (33028941).

Almost surely, 2^66057881 is an apocalyptic number.

It is an amenable number.

66057881 is a deficient number, since it is larger than the sum of its proper divisors (1).

66057881 is an equidigital number, since it uses as much as digits as its factorization.

66057881 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 80640, while the sum is 41.

The square root of 66057881 is about 8127.5999532457. The cubic root of 66057881 is about 404.2421044199.

The spelling of 66057881 in words is "sixty-six million, fifty-seven thousand, eight hundred eighty-one".