640155428641 has 4 divisors (see below), whose sum is σ = 640801398784. Its totient is φ = 639509458500.

The previous prime is 640155428623. The next prime is 640155428659. The reversal of 640155428641 is 146824551046.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (640155428623) and next prime (640155428659).

It is a cyclic number.

It is not a de Polignac number, because 640155428641 - 2¹¹ = 640155426593 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 640155428591 and 640155428600.

It is not an unprimeable number, because it can be changed into a prime (640155425641) 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 3 ways as a sum of consecutive naturals, for example, 322983585 + ... + 322985566.

It is an arithmetic number, because the mean of its divisors is an integer number (160200349696).

Almost surely, 2^640155428641 is an apocalyptic number.

It is an amenable number.

640155428641 is a deficient number, since it is larger than the sum of its proper divisors (645970143).

640155428641 is an equidigital number, since it uses as much as digits as its factorization.

640155428641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 645970142.

The product of its (nonzero) digits is 921600, while the sum is 46.

Adding to 640155428641 its reverse (146824551046), we get a palindrome (786979979687).

The spelling of 640155428641 in words is "six hundred forty billion, one hundred fifty-five million, four hundred twenty-eight thousand, six hundred forty-one".