20155423205 has 4 divisors (see below), whose sum is σ = 24186507852. Its totient is φ = 16124338560.

The previous prime is 20155423157. The next prime is 20155423207. The reversal of 20155423205 is 50232455102.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 50232455102 = 2 ⋅25116227551.

It can be written as a sum of positive squares in 2 ways, for example, as 8584763716 + 11570659489 = 92654^2 + 107567^2 .

It is not a de Polignac number, because 20155423205 - 2⁸ = 20155422949 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 (20155423207) 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, 2015542316 + ... + 2015542325.

It is an arithmetic number, because the mean of its divisors is an integer number (6046626963).

Almost surely, 2^20155423205 is an apocalyptic number.

It is an amenable number.

20155423205 is a deficient number, since it is larger than the sum of its proper divisors (4031084647).

20155423205 is an equidigital number, since it uses as much as digits as its factorization.

20155423205 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4031084646.

The product of its (nonzero) digits is 12000, while the sum is 29.

Adding to 20155423205 its reverse (50232455102), we get a palindrome (70387878307).

The spelling of 20155423205 in words is "twenty billion, one hundred fifty-five million, four hundred twenty-three thousand, two hundred five".