642211781686 has 8 divisors (see below), whose sum is σ = 964600388064. Its totient is φ = 320678319000.

The previous prime is 642211781647. The next prime is 642211781689. The reversal of 642211781686 is 686187112246.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (642211781689) 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 3 ways as a sum of consecutive naturals, for example, 213784045 + ... + 213787048.

It is an arithmetic number, because the mean of its divisors is an integer number (120575048508).

Almost surely, 2^642211781686 is an apocalyptic number.

642211781686 is a deficient number, since it is larger than the sum of its proper divisors (322388606378).

642211781686 is a wasteful number, since it uses less digits than its factorization.

642211781686 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 427571846.

The product of its digits is 1548288, while the sum is 52.

The spelling of 642211781686 in words is "six hundred forty-two billion, two hundred eleven million, seven hundred eighty-one thousand, six hundred eighty-six".