642105842638 has 16 divisors (see below), whose sum is σ = 1070707510656. Its totient is φ = 286796653920.

The previous prime is 642105842603. The next prime is 642105842663. The reversal of 642105842638 is 836248501246.

It is a junction number, because it is equal to n+sod(n) for n = 642105842591 and 642105842600.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 398327881 + ... + 398329492.

It is an arithmetic number, because the mean of its divisors is an integer number (66919219416).

Almost surely, 2^642105842638 is an apocalyptic number.

642105842638 is a deficient number, since it is larger than the sum of its proper divisors (428601668018).

642105842638 is a wasteful number, since it uses less digits than its factorization.

642105842638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 796657419.

The product of its (nonzero) digits is 2211840, while the sum is 49.

The spelling of 642105842638 in words is "six hundred forty-two billion, one hundred five million, eight hundred forty-two thousand, six hundred thirty-eight".