20255493917 has 4 divisors (see below), whose sum is σ = 20749530396. Its totient is φ = 19761457440.

The previous prime is 20255493911. The next prime is 20255493919. The reversal of 20255493917 is 71939455202.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 71939455202 = 2 ⋅35969727601.

It can be written as a sum of positive squares in 2 ways, for example, as 1318706596 + 18936787321 = 36314^2 + 137611^2 .

It is a cyclic number.

It is not a de Polignac number, because 20255493917 - 2⁴ = 20255493901 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20255493911) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 247018178 + ... + 247018259.

It is an arithmetic number, because the mean of its divisors is an integer number (5187382599).

Almost surely, 2^20255493917 is an apocalyptic number.

It is an amenable number.

20255493917 is a deficient number, since it is larger than the sum of its proper divisors (494036479).

20255493917 is an equidigital number, since it uses as much as digits as its factorization.

20255493917 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 494036478.

The product of its (nonzero) digits is 680400, while the sum is 47.

The spelling of 20255493917 in words is "twenty billion, two hundred fifty-five million, four hundred ninety-three thousand, nine hundred seventeen".