640323426653 has 4 divisors (see below), whose sum is σ = 642257938848. Its totient is φ = 638388914460.

The previous prime is 640323426647. The next prime is 640323426707. The reversal of 640323426653 is 356624323046.

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 a cyclic number.

It is not a de Polignac number, because 640323426653 - 2¹⁰ = 640323425629 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 (640323426053) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 967255601 + ... + 967256262.

It is an arithmetic number, because the mean of its divisors is an integer number (160564484712).

Almost surely, 2^640323426653 is an apocalyptic number.

It is an amenable number.

640323426653 is a deficient number, since it is larger than the sum of its proper divisors (1934512195).

640323426653 is a wasteful number, since it uses less digits than its factorization.

640323426653 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1934512194.

The product of its (nonzero) digits is 1866240, while the sum is 44.

Adding to 640323426653 its reverse (356624323046), we get a palindrome (996947749699).

The spelling of 640323426653 in words is "six hundred forty billion, three hundred twenty-three million, four hundred twenty-six thousand, six hundred fifty-three".