20873351421785 has 4 divisors (see below), whose sum is σ = 25048021706148. Its totient is φ = 16698681137424.

The previous prime is 20873351421779. The next prime is 20873351421869. The reversal of 20873351421785 is 58712415337802.

It is a happy number.

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 9415992965401 + 11457358456384 = 3068549^2 + 3384872^2 .

It is a cyclic number.

It is not a de Polignac number, because 20873351421785 - 2¹⁸ = 20873351159641 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 20873351421785.

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, 2087335142174 + ... + 2087335142183.

It is an arithmetic number, because the mean of its divisors is an integer number (6262005426537).

Almost surely, 2^{20873351421785} is an apocalyptic number.

It is an amenable number.

20873351421785 is a deficient number, since it is larger than the sum of its proper divisors (4174670284363).

20873351421785 is an equidigital number, since it uses as much as digits as its factorization.

20873351421785 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4174670284362.

The product of its (nonzero) digits is 11289600, while the sum is 56.

The spelling of 20873351421785 in words is "twenty trillion, eight hundred seventy-three billion, three hundred fifty-one million, four hundred twenty-one thousand, seven hundred eighty-five".