66549999973 has 2 divisors, whose sum is σ = 66549999974. Its totient is φ = 66549999972.

The previous prime is 66549999941. The next prime is 66550000043. The reversal of 66549999973 is 37999994566.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 49482667809 + 17067332164 = 222447^2 + 130642^2 .

It is a cyclic number.

It is not a de Polignac number, because 66549999973 - 2⁵ = 66549999941 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 66549999973.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66549991973) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33274999986 + 33274999987.

It is an arithmetic number, because the mean of its divisors is an integer number (33274999987).

Almost surely, 2^66549999973 is an apocalyptic number.

It is an amenable number.

66549999973 is a deficient number, since it is larger than the sum of its proper divisors (1).

66549999973 is an equidigital number, since it uses as much as digits as its factorization.

66549999973 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 892820880, while the sum is 76.

The spelling of 66549999973 in words is "sixty-six billion, five hundred forty-nine million, nine hundred ninety-nine thousand, nine hundred seventy-three".