640464001243 has 4 divisors (see below), whose sum is σ = 698688001368. Its totient is φ = 582240001120.

The previous prime is 640464001223. The next prime is 640464001273. The reversal of 640464001243 is 342100464046.

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 640464001243 - 2⁹ = 640464000731 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 640464001199 and 640464001208.

It is not an unprimeable number, because it can be changed into a prime (640464001223) 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, 29112000046 + ... + 29112000067.

It is an arithmetic number, because the mean of its divisors is an integer number (174672000342).

Almost surely, 2^640464001243 is an apocalyptic number.

640464001243 is a deficient number, since it is larger than the sum of its proper divisors (58224000125).

640464001243 is a wasteful number, since it uses less digits than its factorization.

640464001243 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 58224000124.

The product of its (nonzero) digits is 55296, while the sum is 34.

Adding to 640464001243 its reverse (342100464046), we get a palindrome (982564465289).

The spelling of 640464001243 in words is "six hundred forty billion, four hundred sixty-four million, one thousand, two hundred forty-three".