20663530434991 has 2 divisors, whose sum is σ = 20663530434992. Its totient is φ = 20663530434990.

The previous prime is 20663530434979. The next prime is 20663530435001. The reversal of 20663530434991 is 19943403536602.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20663530434991 - 2¹¹ = 20663530432943 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20663530434901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10331765217495 + 10331765217496.

It is an arithmetic number, because the mean of its divisors is an integer number (10331765217496).

Almost surely, 2^{20663530434991} is an apocalyptic number.

20663530434991 is a deficient number, since it is larger than the sum of its proper divisors (1).

20663530434991 is an equidigital number, since it uses as much as digits as its factorization.

20663530434991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 12597120, while the sum is 55.

The spelling of 20663530434991 in words is "twenty trillion, six hundred sixty-three billion, five hundred thirty million, four hundred thirty-four thousand, nine hundred ninety-one".