20640352643 has 8 divisors (see below), whose sum is σ = 21159424176. Its totient is φ = 20123056800.

The previous prime is 20640352609. The next prime is 20640352679. The reversal of 20640352643 is 34625304602.

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 20640352643 - 2³² = 16345385347 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20640352043) 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, 420368 + ... + 466893.

It is an arithmetic number, because the mean of its divisors is an integer number (2644928022).

Almost surely, 2^20640352643 is an apocalyptic number.

20640352643 is a deficient number, since it is larger than the sum of its proper divisors (519071533).

20640352643 is an equidigital number, since it uses as much as digits as its factorization.

20640352643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 887845.

The product of its (nonzero) digits is 103680, while the sum is 35.

The spelling of 20640352643 in words is "twenty billion, six hundred forty million, three hundred fifty-two thousand, six hundred forty-three".