640533554351 has 4 divisors (see below), whose sum is σ = 661195927104. Its totient is φ = 619871181600.

The previous prime is 640533554317. The next prime is 640533554363. The reversal of 640533554351 is 153455335046.

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 640533554351 - 2¹⁰ = 640533553327 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640533553351) 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, 10331186330 + ... + 10331186391.

It is an arithmetic number, because the mean of its divisors is an integer number (165298981776).

Almost surely, 2^640533554351 is an apocalyptic number.

640533554351 is a deficient number, since it is larger than the sum of its proper divisors (20662372753).

640533554351 is a wasteful number, since it uses less digits than its factorization.

640533554351 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20662372752.

The product of its (nonzero) digits is 1620000, while the sum is 44.

Adding to 640533554351 its reverse (153455335046), we get a palindrome (793988889397).

The spelling of 640533554351 in words is "six hundred forty billion, five hundred thirty-three million, five hundred fifty-four thousand, three hundred fifty-one".