640131563426 has 4 divisors (see below), whose sum is σ = 960197345142. Its totient is φ = 320065781712.

The previous prime is 640131563377. The next prime is 640131563429. The reversal of 640131563426 is 624365131046.

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

It can be written as a sum of positive squares in only one way, i.e., 600570751225 + 39560812201 = 774965^2 + 198899^2 .

It is not an unprimeable number, because it can be changed into a prime (640131563429) 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 as a sum of consecutive naturals, namely, 160032890855 + ... + 160032890858.

Almost surely, 2^640131563426 is an apocalyptic number.

640131563426 is a deficient number, since it is larger than the sum of its proper divisors (320065781716).

640131563426 is a wasteful number, since it uses less digits than its factorization.

640131563426 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 320065781715.

The product of its (nonzero) digits is 311040, while the sum is 41.

The spelling of 640131563426 in words is "six hundred forty billion, one hundred thirty-one million, five hundred sixty-three thousand, four hundred twenty-six".