640203023 has 4 divisors (see below), whose sum is σ = 649758360. Its totient is φ = 630647688.

The previous prime is 640203013. The next prime is 640203037. The reversal of 640203023 is 320302046.

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 640203023 - 2⁸ = 640202767 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 640202986 and 640203004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640203013) 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, 4777568 + ... + 4777701.

It is an arithmetic number, because the mean of its divisors is an integer number (162439590).

Almost surely, 2^640203023 is an apocalyptic number.

640203023 is a deficient number, since it is larger than the sum of its proper divisors (9555337).

640203023 is an equidigital number, since it uses as much as digits as its factorization.

640203023 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9555336.

The product of its (nonzero) digits is 864, while the sum is 20.

The square root of 640203023 is about 25302.2335575340. The cubic root of 640203023 is about 861.8649913359.

Adding to 640203023 its reverse (320302046), we get a palindrome (960505069).

The spelling of 640203023 in words is "six hundred forty million, two hundred three thousand, twenty-three".