642657198123 has 10 divisors (see below), whose sum is σ = 960018777564. Its totient is φ = 428438132028.

The previous prime is 642657198091. The next prime is 642657198163. The reversal of 642657198123 is 321891756246.

It is a happy number.

642657198123 is a `hidden beast` number, since 6 + 42 + 6 + 571 + 9 + 8 + 1 + 23 = 666.

It is not a de Polignac number, because 642657198123 - 2⁵ = 642657198091 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 642657198123.

It is not an unprimeable number, because it can be changed into a prime (642657198163) 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 9 ways as a sum of consecutive naturals, for example, 3967019661 + ... + 3967019822.

Almost surely, 2^642657198123 is an apocalyptic number.

642657198123 is a deficient number, since it is larger than the sum of its proper divisors (317361579441).

642657198123 is an equidigital number, since it uses as much as digits as its factorization.

642657198123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7934039495 (or 7934039486 counting only the distinct ones).

The product of its digits is 4354560, while the sum is 54.

The spelling of 642657198123 in words is "six hundred forty-two billion, six hundred fifty-seven million, one hundred ninety-eight thousand, one hundred twenty-three".