20635645549 has 2 divisors, whose sum is σ = 20635645550. Its totient is φ = 20635645548.

The previous prime is 20635645529. The next prime is 20635645567. The reversal of 20635645549 is 94554653602.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14312533225 + 6323112324 = 119635^2 + 79518^2 .

It is a cyclic number.

It is not a de Polignac number, because 20635645549 - 2¹⁷ = 20635514477 is a prime.

It is a super-2 number, since 2×20635645549² (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 (20635645529) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10317822774 + 10317822775.

It is an arithmetic number, because the mean of its divisors is an integer number (10317822775).

Almost surely, 2^20635645549 is an apocalyptic number.

It is an amenable number.

20635645549 is a deficient number, since it is larger than the sum of its proper divisors (1).

20635645549 is an equidigital number, since it uses as much as digits as its factorization.

20635645549 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3888000, while the sum is 49.

The spelling of 20635645549 in words is "twenty billion, six hundred thirty-five million, six hundred forty-five thousand, five hundred forty-nine".