20645646343 has 4 divisors (see below), whose sum is σ = 23595024400. Its totient is φ = 17696268288.

The previous prime is 20645646323. The next prime is 20645646353. The reversal of 20645646343 is 34364654602.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20645646343 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20645646343.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20645646313) 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, 1474689018 + ... + 1474689031.

It is an arithmetic number, because the mean of its divisors is an integer number (5898756100).

Almost surely, 2^20645646343 is an apocalyptic number.

20645646343 is a deficient number, since it is larger than the sum of its proper divisors (2949378057).

20645646343 is an equidigital number, since it uses as much as digits as its factorization.

20645646343 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2949378056.

The product of its (nonzero) digits is 1244160, while the sum is 43.

The spelling of 20645646343 in words is "twenty billion, six hundred forty-five million, six hundred forty-six thousand, three hundred forty-three".