20545457021 has 2 divisors, whose sum is σ = 20545457022. Its totient is φ = 20545457020.

The previous prime is 20545457011. The next prime is 20545457029. The reversal of 20545457021 is 12075454502.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11327344900 + 9218112121 = 106430^2 + 96011^2 .

It is a cyclic number.

It is not a de Polignac number, because 20545457021 - 2¹⁴ = 20545440637 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20545457029) 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, 10272728510 + 10272728511.

It is an arithmetic number, because the mean of its divisors is an integer number (10272728511).

Almost surely, 2^20545457021 is an apocalyptic number.

It is an amenable number.

20545457021 is a deficient number, since it is larger than the sum of its proper divisors (1).

20545457021 is an equidigital number, since it uses as much as digits as its factorization.

20545457021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 56000, while the sum is 35.

The spelling of 20545457021 in words is "twenty billion, five hundred forty-five million, four hundred fifty-seven thousand, twenty-one".