20640017797 has 16 divisors (see below), whose sum is σ = 24116400000. Its totient is φ = 17657334240.

The previous prime is 20640017777. The next prime is 20640017819. The reversal of 20640017797 is 79771004602.

It is a de Polignac number, because none of the positive numbers 2^k-20640017797 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20640017777) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 120954 + ... + 236452.

It is an arithmetic number, because the mean of its divisors is an integer number (1507275000).

Almost surely, 2^20640017797 is an apocalyptic number.

It is an amenable number.

20640017797 is a deficient number, since it is larger than the sum of its proper divisors (3476382203).

20640017797 is an equidigital number, since it uses as much as digits as its factorization.

20640017797 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 116041 (or 116027 counting only the distinct ones).

The product of its (nonzero) digits is 148176, while the sum is 43.

The spelling of 20640017797 in words is "twenty billion, six hundred forty million, seventeen thousand, seven hundred ninety-seven".