20545208897 has 4 divisors (see below), whose sum is σ = 20600290260. Its totient is φ = 20490127536.

The previous prime is 20545208851. The next prime is 20545208911. The reversal of 20545208897 is 79880254502.

It is a Cunningham number, because it is equal to 143336²+1.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 79880254502 = 2 ⋅39940127251.

It can be written as a sum of positive squares in 2 ways, for example, as 11167416976 + 9377791921 = 105676^2 + 96839^2 .

It is a cyclic number.

It is not a de Polignac number, because 20545208897 - 2¹⁴ = 20545192513 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20545208807) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 27540122 + ... + 27540867.

It is an arithmetic number, because the mean of its divisors is an integer number (5150072565).

Almost surely, 2^20545208897 is an apocalyptic number.

It is an amenable number.

20545208897 is a deficient number, since it is larger than the sum of its proper divisors (55081363).

20545208897 is an equidigital number, since it uses as much as digits as its factorization.

20545208897 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55081362.

The product of its (nonzero) digits is 1612800, while the sum is 50.

The spelling of 20545208897 in words is "twenty billion, five hundred forty-five million, two hundred eight thousand, eight hundred ninety-seven".