20909042485085 has 4 divisors (see below), whose sum is σ = 25090850982108. Its totient is φ = 16727233988064.

The previous prime is 20909042485063. The next prime is 20909042485117. The reversal of 20909042485085 is 58058424090902.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 2795353268761 + 18113689216324 = 1671931^2 + 4256018^2 .

It is a cyclic number.

It is not a de Polignac number, because 20909042485085 - 2²⁸ = 20908774049629 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20909042485085.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2090904248504 + ... + 2090904248513.

It is an arithmetic number, because the mean of its divisors is an integer number (6272712745527).

Almost surely, 2^{20909042485085} is an apocalyptic number.

It is an amenable number.

20909042485085 is a deficient number, since it is larger than the sum of its proper divisors (4181808497023).

20909042485085 is an equidigital number, since it uses as much as digits as its factorization.

20909042485085 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4181808497022.

The product of its (nonzero) digits is 8294400, while the sum is 56.

The spelling of 20909042485085 in words is "twenty trillion, nine hundred nine billion, forty-two million, four hundred eighty-five thousand, eighty-five".