20295645581 has 2 divisors, whose sum is σ = 20295645582. Its totient is φ = 20295645580.

The previous prime is 20295645527. The next prime is 20295645583. The reversal of 20295645581 is 18554659202.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18931008100 + 1364637481 = 137590^2 + 36941^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20295645581 is a prime.

It is a super-2 number, since 2×20295645581² (a number of 21 digits) contains 22 as substring.

It is a Sophie Germain prime.

Together with 20295645583, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20295645583) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10147822790 + 10147822791.

It is an arithmetic number, because the mean of its divisors is an integer number (10147822791).

Almost surely, 2^20295645581 is an apocalyptic number.

It is an amenable number.

20295645581 is a deficient number, since it is larger than the sum of its proper divisors (1).

20295645581 is an equidigital number, since it uses as much as digits as its factorization.

20295645581 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 864000, while the sum is 47.

The spelling of 20295645581 in words is "twenty billion, two hundred ninety-five million, six hundred forty-five thousand, five hundred eighty-one".