20405636873 has 4 divisors (see below), whose sum is σ = 20406261120. Its totient is φ = 20405012628.

The previous prime is 20405636851. The next prime is 20405636917. The reversal of 20405636873 is 37863650402.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 37863650402 = 2 ⋅18931825201.

It is a cyclic number.

It is not a de Polignac number, because 20405636873 - 2¹² = 20405632777 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20405636803) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 260213 + ... + 329426.

It is an arithmetic number, because the mean of its divisors is an integer number (5101565280).

Almost surely, 2^20405636873 is an apocalyptic number.

It is an amenable number.

20405636873 is a deficient number, since it is larger than the sum of its proper divisors (624247).

20405636873 is an equidigital number, since it uses as much as digits as its factorization.

20405636873 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 624246.

The product of its (nonzero) digits is 725760, while the sum is 44.

The spelling of 20405636873 in words is "twenty billion, four hundred five million, six hundred thirty-six thousand, eight hundred seventy-three".