1985642564309 has 2 divisors, whose sum is σ = 1985642564310. Its totient is φ = 1985642564308.

The previous prime is 1985642564263. The next prime is 1985642564371. The reversal of 1985642564309 is 9034652465891.

It is an a-pointer prime, because the next prime (1985642564371) can be obtained adding 1985642564309 to its sum of digits (62).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1618436863684 + 367205700625 = 1272178^2 + 605975^2 .

It is a cyclic number.

It is not a de Polignac number, because 1985642564309 - 2⁸ = 1985642564053 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1985642504309) 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, 992821282154 + 992821282155.

It is an arithmetic number, because the mean of its divisors is an integer number (992821282155).

Almost surely, 2^{1985642564309} is an apocalyptic number.

It is an amenable number.

1985642564309 is a deficient number, since it is larger than the sum of its proper divisors (1).

1985642564309 is an equidigital number, since it uses as much as digits as its factorization.

1985642564309 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 55987200, while the sum is 62.

The spelling of 1985642564309 in words is "one trillion, nine hundred eighty-five billion, six hundred forty-two million, five hundred sixty-four thousand, three hundred nine".