20787934081 has 2 divisors, whose sum is σ = 20787934082. Its totient is φ = 20787934080.

The previous prime is 20787934073. The next prime is 20787934099. The reversal of 20787934081 is 18043978702.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12586820481 + 8201113600 = 112191^2 + 90560^2 .

It is a cyclic number.

It is not a de Polignac number, because 20787934081 - 2³ = 20787934073 is a prime.

It is a super-2 number, since 2×20787934081² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (20787934001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10393967040 + 10393967041.

It is an arithmetic number, because the mean of its divisors is an integer number (10393967041).

Almost surely, 2^20787934081 is an apocalyptic number.

It is an amenable number.

20787934081 is a deficient number, since it is larger than the sum of its proper divisors (1).

20787934081 is an equidigital number, since it uses as much as digits as its factorization.

20787934081 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 677376, while the sum is 49.

The spelling of 20787934081 in words is "twenty billion, seven hundred eighty-seven million, nine hundred thirty-four thousand, eighty-one".