642646646245 has 16 divisors (see below), whose sum is σ = 791501563440. Its totient is φ = 500615065600.

The previous prime is 642646646237. The next prime is 642646646267. The reversal of 642646646245 is 542646646246.

It can be written as a sum of positive squares in 8 ways, for example, as 66721989636 + 575924656609 = 258306^2 + 758897^2 .

It is not a de Polignac number, because 642646646245 - 2³ = 642646646237 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2901700 + ... + 3115309.

It is an arithmetic number, because the mean of its divisors is an integer number (49468847715).

Almost surely, 2^642646646245 is an apocalyptic number.

It is an amenable number.

642646646245 is a deficient number, since it is larger than the sum of its proper divisors (148854917195).

642646646245 is a wasteful number, since it uses less digits than its factorization.

642646646245 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6017576.

The product of its digits is 39813120, while the sum is 55.

Subtracting from 642646646245 its reverse (542646646246), we obtain a palindrome (99999999999).

The spelling of 642646646245 in words is "six hundred forty-two billion, six hundred forty-six million, six hundred forty-six thousand, two hundred forty-five".