985661639 has 2 divisors, whose sum is σ = 985661640. Its totient is φ = 985661638.

The previous prime is 985661627. The next prime is 985661641. The reversal of 985661639 is 936166589.

It is a strong prime.

It is an emirp because it is prime and its reverse (936166589) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-985661639 is a prime.

It is a Sophie Germain prime.

Together with 985661641, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (985661539) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 492830819 + 492830820.

It is an arithmetic number, because the mean of its divisors is an integer number (492830820).

Almost surely, 2^985661639 is an apocalyptic number.

985661639 is a deficient number, since it is larger than the sum of its proper divisors (1).

985661639 is an equidigital number, since it uses as much as digits as its factorization.

985661639 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2099520, while the sum is 53.

The square root of 985661639 is about 31395.2486691856. The cubic root of 985661639 is about 995.1975194349.

The spelling of 985661639 in words is "nine hundred eighty-five million, six hundred sixty-one thousand, six hundred thirty-nine".