640630243 has 8 divisors (see below), whose sum is σ = 699194160. Its totient is φ = 582120480.

The previous prime is 640630241. The next prime is 640630259. The reversal of 640630243 is 342036046.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 640630243 - 2¹ = 640630241 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (640630241) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13573 + ... + 38281.

It is an arithmetic number, because the mean of its divisors is an integer number (87399270).

Almost surely, 2^640630243 is an apocalyptic number.

640630243 is a deficient number, since it is larger than the sum of its proper divisors (58563917).

640630243 is a wasteful number, since it uses less digits than its factorization.

640630243 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27077.

The product of its (nonzero) digits is 10368, while the sum is 28.

The square root of 640630243 is about 25310.6744872593. The cubic root of 640630243 is about 862.0566618295.

Adding to 640630243 its reverse (342036046), we get a palindrome (982666289).

The spelling of 640630243 in words is "six hundred forty million, six hundred thirty thousand, two hundred forty-three".