20981327663 has 2 divisors, whose sum is σ = 20981327664. Its totient is φ = 20981327662.

The previous prime is 20981327567. The next prime is 20981327677. The reversal of 20981327663 is 36672318902.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20981327663 - 2²⁴ = 20964550447 is a prime.

It is a super-2 number, since 2×20981327663² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20981327963) 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 as a sum of consecutive naturals, namely, 10490663831 + 10490663832.

It is an arithmetic number, because the mean of its divisors is an integer number (10490663832).

Almost surely, 2^20981327663 is an apocalyptic number.

20981327663 is a deficient number, since it is larger than the sum of its proper divisors (1).

20981327663 is an equidigital number, since it uses as much as digits as its factorization.

20981327663 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 653184, while the sum is 47.

The spelling of 20981327663 in words is "twenty billion, nine hundred eighty-one million, three hundred twenty-seven thousand, six hundred sixty-three".