20640744798 has 8 divisors (see below), whose sum is σ = 41281489608. Its totient is φ = 6880248264.

The previous prime is 20640744781. The next prime is 20640744821. The reversal of 20640744798 is 89744704602.

It is a happy number.

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

20640744798 is an admirable number.

It is a self number, because there is not a number n which added to its sum of digits gives 20640744798.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1720062061 + ... + 1720062072.

It is an arithmetic number, because the mean of its divisors is an integer number (5160186201).

Almost surely, 2^20640744798 is an apocalyptic number.

20640744798 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20640744798 is a wasteful number, since it uses less digits than its factorization.

20640744798 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3440124138.

The product of its (nonzero) digits is 2709504, while the sum is 51.

The spelling of 20640744798 in words is "twenty billion, six hundred forty million, seven hundred forty-four thousand, seven hundred ninety-eight".