20663655491 has 8 divisors (see below), whose sum is σ = 21050852400. Its totient is φ = 20277690880.

The previous prime is 20663655451. The next prime is 20663655497. The reversal of 20663655491 is 19455636602.

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

It is a cyclic number.

It is not a de Polignac number, because 20663655491 - 2¹⁰ = 20663654467 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20663655497) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 274190 + ... + 341331.

It is an arithmetic number, because the mean of its divisors is an integer number (2631356550).

Almost surely, 2^20663655491 is an apocalyptic number.

20663655491 is a deficient number, since it is larger than the sum of its proper divisors (387196909).

20663655491 is an equidigital number, since it uses as much as digits as its factorization.

20663655491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 616149.

The product of its (nonzero) digits is 1166400, while the sum is 47.

The spelling of 20663655491 in words is "twenty billion, six hundred sixty-three million, six hundred fifty-five thousand, four hundred ninety-one".