20663543899 has 4 divisors (see below), whose sum is σ = 20663889664. Its totient is φ = 20663198136.

The previous prime is 20663543867. The next prime is 20663543909. The reversal of 20663543899 is 99834536602.

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

It is a cyclic number.

It is not a de Polignac number, because 20663543899 - 2⁵ = 20663543867 is a prime.

It is a deceptive number, since it divides R_20663543898.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20663543099) 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, 57627 + ... + 211300.

It is an arithmetic number, because the mean of its divisors is an integer number (5165972416).

Almost surely, 2^20663543899 is an apocalyptic number.

20663543899 is the 76837-th nonagonal number.

20663543899 is a deficient number, since it is larger than the sum of its proper divisors (345765).

20663543899 is an equidigital number, since it uses as much as digits as its factorization.

20663543899 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 345764.

The product of its (nonzero) digits is 8398080, while the sum is 55.

The spelling of 20663543899 in words is "twenty billion, six hundred sixty-three million, five hundred forty-three thousand, eight hundred ninety-nine".