20765357823821 has 8 divisors (see below), whose sum is σ = 22362815775384. Its totient is φ = 19167917405760.

The previous prime is 20765357823701. The next prime is 20765357823823. The reversal of 20765357823821 is 12832875356702.

It can be written as a sum of positive squares in 4 ways, for example, as 5204265813796 + 15561092010025 = 2281286^2 + 3944755^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20765357823821 - 2³⁸ = 20490479916877 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 (20765357823823) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1870250 + ... + 6710331.

It is an arithmetic number, because the mean of its divisors is an integer number (2795351971923).

Almost surely, 2^{20765357823821} is an apocalyptic number.

It is an amenable number.

20765357823821 is a deficient number, since it is larger than the sum of its proper divisors (1597457951563).

20765357823821 is a wasteful number, since it uses less digits than its factorization.

20765357823821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8766751.

The product of its (nonzero) digits is 33868800, while the sum is 59.

The spelling of 20765357823821 in words is "twenty trillion, seven hundred sixty-five billion, three hundred fifty-seven million, eight hundred twenty-three thousand, eight hundred twenty-one".