642684368161 has 16 divisors (see below), whose sum is σ = 742496181120. Its totient is φ = 549783566080.

The previous prime is 642684368149. The next prime is 642684368167. The reversal of 642684368161 is 161863486246.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 642684368161 - 2⁵ = 642684368129 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (642684368167) 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 in 15 ways as a sum of consecutive naturals, for example, 639180 + ... + 1301506.

It is an arithmetic number, because the mean of its divisors is an integer number (46406011320).

Almost surely, 2^642684368161 is an apocalyptic number.

It is an amenable number.

642684368161 is a deficient number, since it is larger than the sum of its proper divisors (99811812959).

642684368161 is a wasteful number, since it uses less digits than its factorization.

642684368161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 667544.

The product of its digits is 7962624, while the sum is 55.

The spelling of 642684368161 in words is "six hundred forty-two billion, six hundred eighty-four million, three hundred sixty-eight thousand, one hundred sixty-one".