640220145623 has 16 divisors (see below), whose sum is σ = 680229627840. Its totient is φ = 601706592000.

The previous prime is 640220145619. The next prime is 640220145659. The reversal of 640220145623 is 326541022046.

It is a cyclic number.

It is not a de Polignac number, because 640220145623 - 2² = 640220145619 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 (640220145023) 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 15 ways as a sum of consecutive naturals, for example, 1936043 + ... + 2242476.

It is an arithmetic number, because the mean of its divisors is an integer number (42514351740).

Almost surely, 2^640220145623 is an apocalyptic number.

640220145623 is a deficient number, since it is larger than the sum of its proper divisors (40009482217).

640220145623 is a wasteful number, since it uses less digits than its factorization.

640220145623 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4178698.

The product of its (nonzero) digits is 69120, while the sum is 35.

Adding to 640220145623 its reverse (326541022046), we get a palindrome (966761167669).

The spelling of 640220145623 in words is "six hundred forty billion, two hundred twenty million, one hundred forty-five thousand, six hundred twenty-three".