20510825081 has 2 divisors, whose sum is σ = 20510825082. Its totient is φ = 20510825080.

The previous prime is 20510825053. The next prime is 20510825087. The reversal of 20510825081 is 18052801502.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13834464400 + 6676360681 = 117620^2 + 81709^2 .

It is a cyclic number.

It is not a de Polignac number, because 20510825081 - 2⁶ = 20510825017 is a prime.

It is a super-2 number, since 2×20510825081² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (20510825087) 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, 10255412540 + 10255412541.

It is an arithmetic number, because the mean of its divisors is an integer number (10255412541).

Almost surely, 2^20510825081 is an apocalyptic number.

It is an amenable number.

20510825081 is a deficient number, since it is larger than the sum of its proper divisors (1).

20510825081 is an equidigital number, since it uses as much as digits as its factorization.

20510825081 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6400, while the sum is 32.

The spelling of 20510825081 in words is "twenty billion, five hundred ten million, eight hundred twenty-five thousand, eighty-one".