20397813697646 has 128 divisors (see below), whose sum is σ = 38980452234240. Its totient is φ = 7774975641600.

The previous prime is 20397813697633. The next prime is 20397813697649. The reversal of 20397813697646 is 64679631879302.

It is a self number, because there is not a number n which added to its sum of digits gives 20397813697646.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20397813697649) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1543061225 + ... + 1543074443.

It is an arithmetic number, because the mean of its divisors is an integer number (304534783080).

Almost surely, 2^{20397813697646} is an apocalyptic number.

20397813697646 is a deficient number, since it is larger than the sum of its proper divisors (18582638536594).

20397813697646 is a wasteful number, since it uses less digits than its factorization.

20397813697646 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14170.

The product of its (nonzero) digits is 493807104, while the sum is 71.

The spelling of 20397813697646 in words is "twenty trillion, three hundred ninety-seven billion, eight hundred thirteen million, six hundred ninety-seven thousand, six hundred forty-six".