20981776973 has 2 divisors, whose sum is σ = 20981776974. Its totient is φ = 20981776972.

The previous prime is 20981776957. The next prime is 20981777039. The reversal of 20981776973 is 37967718902.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11494627369 + 9487149604 = 107213^2 + 97402^2 .

It is a cyclic number.

It is not a de Polignac number, because 20981776973 - 2⁴ = 20981776957 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20981776273) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10490888486 + 10490888487.

It is an arithmetic number, because the mean of its divisors is an integer number (10490888487).

Almost surely, 2^20981776973 is an apocalyptic number.

It is an amenable number.

20981776973 is a deficient number, since it is larger than the sum of its proper divisors (1).

20981776973 is an equidigital number, since it uses as much as digits as its factorization.

20981776973 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8001504, while the sum is 59.

The spelling of 20981776973 in words is "twenty billion, nine hundred eighty-one million, seven hundred seventy-six thousand, nine hundred seventy-three".