66503980891 has 2 divisors, whose sum is σ = 66503980892. Its totient is φ = 66503980890.

The previous prime is 66503980889. The next prime is 66503980951. The reversal of 66503980891 is 19808930566.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 66503980891 - 2¹ = 66503980889 is a prime.

Together with 66503980889, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (66503980811) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33251990445 + 33251990446.

It is an arithmetic number, because the mean of its divisors is an integer number (33251990446).

Almost surely, 2^66503980891 is an apocalyptic number.

66503980891 is a deficient number, since it is larger than the sum of its proper divisors (1).

66503980891 is an equidigital number, since it uses as much as digits as its factorization.

66503980891 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2799360, while the sum is 55.

The spelling of 66503980891 in words is "sixty-six billion, five hundred three million, nine hundred eighty thousand, eight hundred ninety-one".