642637373791 has 4 divisors (see below), whose sum is σ = 734442712912. Its totient is φ = 550832034672.

The previous prime is 642637373737. The next prime is 642637373797. The reversal of 642637373791 is 197373736246.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-642637373791 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (642637373797) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 45902669550 + ... + 45902669563.

It is an arithmetic number, because the mean of its divisors is an integer number (183610678228).

Almost surely, 2^642637373791 is an apocalyptic number.

642637373791 is a deficient number, since it is larger than the sum of its proper divisors (91805339121).

642637373791 is an equidigital number, since it uses as much as digits as its factorization.

642637373791 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 91805339120.

The product of its digits is 24004512, while the sum is 58.

The spelling of 642637373791 in words is "six hundred forty-two billion, six hundred thirty-seven million, three hundred seventy-three thousand, seven hundred ninety-one".