20979175663 has 2 divisors, whose sum is σ = 20979175664. Its totient is φ = 20979175662.

The previous prime is 20979175661. The next prime is 20979175681. The reversal of 20979175663 is 36657197902.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20979175663 - 2¹ = 20979175661 is a prime.

It is a super-2 number, since 2×20979175663² (a number of 21 digits) contains 22 as substring.

Together with 20979175661, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20979175661) 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, 10489587831 + 10489587832.

It is an arithmetic number, because the mean of its divisors is an integer number (10489587832).

Almost surely, 2^20979175663 is an apocalyptic number.

20979175663 is a deficient number, since it is larger than the sum of its proper divisors (1).

20979175663 is an equidigital number, since it uses as much as digits as its factorization.

20979175663 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4286520, while the sum is 55.

The spelling of 20979175663 in words is "twenty billion, nine hundred seventy-nine million, one hundred seventy-five thousand, six hundred sixty-three".