21020000020997 has 2 divisors, whose sum is σ = 21020000020998. Its totient is φ = 21020000020996.

The previous prime is 21020000020979. The next prime is 21020000021029. The reversal of 21020000020997 is 79902000002012.

Together with previous prime (21020000020979) it forms an Ormiston pair, because they use the same digits, order apart.

It is an a-pointer prime, because the next prime (21020000021029) can be obtained adding 21020000020997 to its sum of digits (32).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17049887980801 + 3970112040196 = 4129151^2 + 1992514^2 .

It is a cyclic number.

It is not a de Polignac number, because 21020000020997 - 2⁸ = 21020000020741 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21020000022997) 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, 10510000010498 + 10510000010499.

It is an arithmetic number, because the mean of its divisors is an integer number (10510000010499).

Almost surely, 2^{21020000020997} is an apocalyptic number.

It is an amenable number.

21020000020997 is a deficient number, since it is larger than the sum of its proper divisors (1).

21020000020997 is an equidigital number, since it uses as much as digits as its factorization.

21020000020997 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4536, while the sum is 32.

The spelling of 21020000020997 in words is "twenty-one trillion, twenty billion, twenty thousand, nine hundred ninety-seven".