640322431631 has 4 divisors (see below), whose sum is σ = 640474857264. Its totient is φ = 640170006000.

The previous prime is 640322431627. The next prime is 640322431633. The reversal of 640322431631 is 136134223046.

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

It is a cyclic number.

It is not a de Polignac number, because 640322431631 - 2² = 640322431627 is a prime.

It is a super-2 number, since 2×640322431631² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 640322431591 and 640322431600.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640322431633) 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, 76206515 + ... + 76214916.

It is an arithmetic number, because the mean of its divisors is an integer number (160118714316).

Almost surely, 2^640322431631 is an apocalyptic number.

640322431631 is a deficient number, since it is larger than the sum of its proper divisors (152425633).

640322431631 is a wasteful number, since it uses less digits than its factorization.

640322431631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 152425632.

The product of its (nonzero) digits is 62208, while the sum is 35.

Adding to 640322431631 its reverse (136134223046), we get a palindrome (776456654677).

The spelling of 640322431631 in words is "six hundred forty billion, three hundred twenty-two million, four hundred thirty-one thousand, six hundred thirty-one".